Binder for monolithic refractories, monolithic refractory, and construction method of monolithic refractories

ABSTRACT

This binder for monolithic refractories includes a solid solution obtained by dissolving Ca components in α-SrAl 2 O 4  or β-SrAl 2 O 4 , wherein when the Ca components are dissolved in the α-SrAl 2 O 4 , a crystallite diameter of the solid solution is from 40 nm to 75 nm, and when the Ca components are dissolved in the β-SrAl 2 O 4 , a crystallite diameter of the solid solution is from 35 nm to 70 nm.

FIELD OF THE INVENTION

The present invention relates to a binder for monolithic refractories, which is used for the lining or repair of furnaces, a monolithic refractory, and a construction method of monolithic refractories.

This application is a national stage application of International Application No. PCT/JP2011/060452, filed Apr. 28, 2011, which claims priority to Japanese Patent Application No. 2010-104559, filed Apr. 28, 2010, the content of which is incorporated herein by reference.

RELATED ART

As a binder for the lining refractories of furnaces used for a variety of high temperature processes, best exemplified by steel processes, a number of organic and inorganic compounds, such as sodium phosphate, sodium silicate, a furan resin, a phenol resin, pitch, aluminum lactate, sodium aluminate, silica sol, alumina sol, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, ethylsilicate, alumina cement, hydraulic alumina, or the like, are used.

In recent years, refractories have become unshaped for improvement in constructability, ease of repair, or the like, and monolithic refractories have become widely used even in parts that come into contact with molten iron or high temperature slag, for which shaped bricks were used in the past.

The manufacture of monolithic refractories does not include a high pressure press, which is performed in the manufacture of shaped refractories. Therefore, the characteristics of raw materials or binders for a filling property, firmness, and development of strength are particularly important. Among them, alumina cement (major chemical compounds: CaO.Al₂O₃, CaO.2Al₂O₃, 12CaO.7Al₂O₃) is used for a wide range of uses as a binder for refractories of degassing and secondary refining facilities such as a blast furnace runner, a molten steel ladle, or RH; a tundish; a heating furnace; heat treatment furnace; and the like.

Furthermore, investigations are also ongoing with alumina-based binders including chemical components other than CaO—Al₂O₃.

For examples, Patent Documents 1 and 2 disclose mixtures of raw materials for the manufacture of refractory alumina cement including barium or strontium and alumina as the main chemical components. Specifically, the mixtures of raw materials for the manufacture of cement are obtained by appropriately performing a thermal treatment on mixtures of carbonates and chlorides.

Non-Patent Document 1 discloses a material produced by adding a commercial high-purity reagent to CaO—SrO—Al₂O₃-based cement and then blending and firing the mixture, which shows a property of being hardened with an addition of water.

In addition, Patent Document 3 discloses a binder for monolithic refractories using mixtures of raw materials for the manufacture of cement having CaO—SrO—Al₂O₃ composition, which shows improved high-temperature slag resistance, compared to binders with CaO—Al₂O₃ composition.

REFERENCE DOCUMENTS Patent Documents

-   [Patent Document 1] Japanese Unexamined Patent Application, First     Publication No. S52-148524 -   [Patent Document 2] Japanese Unexamined Patent Application, First     Publication No. S58-26079 -   [Patent Document 3] Japanese Unexamined Patent Application, First     Publication No. 2008-290934

Non-Patent Documents

-   [Non-Patent Document 1] Ito, Mizuno, Kawano, Suzuki: Journal of the     Ceramic Society of Japan, 89, 10, P. 572-577, 1981 -   [Non-Patent Document 2] Prodjosantoso, A. K. and B. J. Kennedy,     Journal of Solid State Chemistry, 2002, Vol. 168, No. 1, pp. 229-236

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, the demand for improvement in steel quality tends to make conditions, such as operation temperature, or the like, more severe and thus high temperature corrosion resistance, or the like is continuously becoming insufficient in conventional binders. Compared to chemical components in refractory aggregates for monolithic refractories, binders including alumina cement, which are generally used, have problems in that they are liable to form low melting point materials due to ferric oxides in molten iron or slag, and wear or infiltration proceeds from binder portions in refractories, which makes it impossible to sufficiently develop the intrinsic tolerance of chemical components in the refractory aggregates.

That is, Patent Document 1 supplies the mixtures of raw materials for the manufacture of refractory alumina cement including barium or strontium and alumina as the main chemical components, and studies the strength, or the like of clinker binders using the mixtures of raw materials. However, the compressive strength is not sufficiently developed 3 days and 7 days after the manufacture and eventually reaches the maximum on the 28 days after the manufacture.

Generally, monolithic refractories are subjected to drying and heating 1 day after the manufacture and are often placed under the operating environment. From such a viewpoint, development of the maximum strength within 24 hours is strongly required. As a result, binders whose maximum strength is eventually developed on the 28 days after manufacture cannot be adopted for monolithic refractories.

In addition, Patent Document 1 discloses nothing about high temperature characteristics of higher than 1000° C. and furthermore is not clear about corrosion resistance with respect to high temperature molten iron or slag and discloses nothing about methods for the application to monolithic refractories with excellent high temperature corrosion resistance.

In addition, Patent Document 2 supplies heat-insulating castable mixtures using strontium aluminate as a binder, with which heat-insulating materials with high temperature strength can be obtained. However, the document is about heat-insulating uses for which the mixtures are lined on the rear surface of furnaces, and therefore is not clear about corrosion resistance with respect to high temperature molten iron or slag, which is an essential characteristic for the wear lining of furnaces. In addition, when strontium aluminate is used as a binder, strontium ions are liable to be eluted during mixing, which easily leads to agglomeration. Accordingly, it becomes clear that there are cases where the construction of the heat-insulating castable mixtures using strontium aluminate as a binder is difficult.

In addition, Non-Patent Document 1 shows that CaO—SrO—Al₂O₃-based cement is produced and the strength of hardened bodies becomes extremely great at an amount of Sr-substitution of from 0.3 mol to 0.4 mol. However, the document discloses nothing about high temperature characteristics of higher than 1000° C., and also shows nothing about methods for the application to monolithic refractories with excellent high temperature corrosion resistance.

Due to the above limitations, as binders for monolithic refractories in actual industrial uses, alumina cement including CaO.Al₂O₃, as the major chemical component, α-Al₂O₃ or CaO.2Al₂O₃, 12CaO.7Al₂O₃ and a variety of additives are used.

In addition, Non-Patent Document 2 shows that a crystal structure of a CaAl₂O₄—SrAl₂O₄ solid solution varies depending on the amount of Ca or Sr solidified. The Introduction thereof shows that CaAl₂O₄ is the major chemical component of high alumina cement used for a heat-resistant castable in the steel industry. However, the document discloses or suggests nothing relating to performance, for example, the strength or corrosion resistance of monolithic refractories when the CaAl₂O₄—SrAl₂O₄ solid solution is used as a binder for monolithic refractories.

That is, as of now, examples of alumina cement used as binders for monolithic refractories include “high alumina cement ES”, “high alumina cement VS-2”, “high alumina cement super 90”, “high alumina cement super G”, “high alumina cement super 2”, “high alumina cement super”, or the like (all product names, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha); “SECAR 71”, “SECAR 80”, or the like (all product names, manufactured by Kerneos Inc.); or the like. Any of the above includes CaO.Al₂O₃, as the major chemical component, α-Al₂O₃ or CaO.2Al₂O₃, 12CaO.7Al₂O₃, and a small amount of additives depending on required characteristics.

As a result, there has been a strong demand for the development of binders for monolithic refractories with excellent corrosion resistance with respect to high temperature molten iron or slag because conditions such as operation temperature continuously become more severe.

On the other hand, Patent Document 3 discloses Ca_(x)Sr_(1-x)Al₂O₄ as binders having excellent corrosion resistance with respect to slag or molten iron, compared to alumina cement in the conventional technology. However, in order for Ca_(x)Sr_(1-x)Al₂O₄ to be widely used as binders of monolithic refractories of furnaces having various thicknesses and shapes and the like, further improvement of hardened strength is required.

An object of the present invention is to provide a binder for monolithic refractories having excellent corrosion resistance with respect to slag or molten iron and excellent characteristics in the early development of hardened strength and the stability thereof, compared to binders such as alumina cement in the conventional technology; a monolithic refractory using the binder; and a construction method of the monolithic refractory.

Methods for Solving the Problem

The inventors paid attention to substituting Ca in a binder for monolithic refractories with a metal atom from the viewpoint of improving the refractoriness of a monolithic refractory, and newly found that, by dissolving SrO in CaO.Al₂O₃ which is a component of alumina cement in the conventional technology (in other words, by dissolving Ca components in SrAl₂O₄ to obtain a solid solution), a composition has a high melting point, corrosion resistance with respect to slag or molten iron is excellent, and constructability and high temperature stability can be improved (refer to Patent Document 3). In addition, the inventors also found that due to the solidification of SrO, a time taken to develop strength of a monolithic refractory can be shortened and thus high strength can be realized (refer to Patent Document 3).

The inventors newly paid attention to a crystallite diameter of the above-described solid solution and vigorously studied and discussed; and as a result, found that, when the crystallite diameter is set to be a predetermined size or less smaller than that in the conventional technology, corrosion resistance and a strength developing property can be further improved and completed the present invention.

Here, the solidification represents two or more kinds of elements (which may be metal or non-metal) dissolving each other such that the entire mixture is uniformly solid. In addition, the solid solution represents a phase of a crystalline material which is formed by two or more kinds of elements becoming uniformly solid.

The summary of the present invention is as follows.

(1) A binder for monolithic refractories including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ or β-SrAl₂O₄, wherein when the Ca components are dissolved in the α-SrAl₂O₄, a crystallite diameter of the solid solution is from 40 nm to 75 nm, and when the Ca components are dissolved in the β-SrAl₂O₄, a crystallite diameter of the solid solution is from 35 nm to 70 nm.

(2) The binder for monolithic refractories according to (1) above, wherein an amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ or the β-SrAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.

(3) The binder for monolithic refractories according to (1) above, further including, as a mixture, a solid solution obtained by dissolving Sr components in CaAl₂O₄, wherein a crystallite diameter of the solid solution is from 25 nm to 60 nm.

(4) The binder for monolithic refractories according to (3) above, wherein an amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ or the β-SrAl₂O₄ and the solid solution obtained by dissolving Sr components in the CaAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.

(5) The binder for monolithic refractories according to (1) above, wherein both of a solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ and a solid solution obtained by dissolving Ca components in the β-SrAl₂O₄ are included as a mixture.

(6) The binder for monolithic refractories according to (5) above, wherein a total amount of both of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ and the solid solution obtained by dissolving Ca components in the β-SrAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.

(7) The binder for monolithic refractories according to (5) above, further including, as a mixture the solid solution obtained by dissolving Sr components in the CaAl₂O₄.

(8) The binder for monolithic refractories according to (7) above, wherein a total amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄, the solid solution obtained by dissolving Ca components in the β-SrAl₂O₄, and the solid solution obtained by dissolving Sr components in the CaAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.

(9) The binder for monolithic refractories according to (1) above, wherein one kind or two or more kinds selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO are included in the binder for monolithic refractories and an amount thereof is 12 mass % or less.

(10) The binder for monolithic refractories according to (1) above, wherein at least one of a dispersant and a hardening retardant is blended into the binder for monolithic refractories.

(11) A monolithic refractory obtained by blending the binder for monolithic refractories according to any one of (1) to (10) above into a refractory aggregate.

(12) The monolithic refractory according to (11) above, wherein the refractory aggregate includes an ultrafine alumina powder with a particle diameter of from 0.8 nm to 1 μm.

(13) The monolithic refractory according to (11) above, wherein an amount of the binder for monolithic refractories is from 0.3 mass % to 20 mass % with respect to 100 mass % of a total amount of the binder for monolithic refractories and the refractory aggregate.

(14) The monolithic refractory according to (13) above, wherein the amount of the binder for monolithic refractories is from 0.5 mass % to 12 mass % with respect to 100 mass % of the total amount of the binder for monolithic refractories and the refractory aggregate.

(15) The monolithic refractory according to (11) above, wherein further at least one of a dispersant, a hardening retardant, and a hardening accelerator is added.

(16) The monolithic refractory according to (15) above, wherein the dispersant is one kind or two or more kinds selected from a group consisting of a polycarbonate-based dispersant, a phosphate-based dispersant, an oxycarboxylic acid, a melamine-based dispersant, a naphthalene-based dispersant, and a lignin sulfonic acid-based dispersant, the hardening accelerator is at least one of an alkali metal salt and aluminate, and the hardening retardant is at least one of boric acid group and silicofluoride.

(17) A construction method of monolithic refractories including: blending and mixing the binder for monolithic refractories according to any one of (1) to (10) above and a refractory aggregate including an ultrafine alumina powder with a particle diameter of 1 μm or less to obtain a monolithic refractory; and constructing the monolithic refractory.

Effects of the Invention

According to a binder for monolithic refractories of the present invention, since a favorable strength developing property is developed within a shorter period of time compared to that of the conventional technology, a time taken to remove a frame can be reduced and construction efficiency can be improved. In addition, it is possible to develop the effects of excellent corrosion resistance with respect to slag or molten iron, and of expansion of the service life of monolithic refractories lined in furnaces used at a high temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a shape of an evaluation specimen.

FIG. 2 is a perspective view showing an external appearance of a rotary corrosion furnace.

FIG. 3 is a cross-sectional view of the rotary corrosion furnace.

EMBODIMENTS OF THE INVENTION

Hereinafter, some embodiments of the present invention will be described.

According to a first embodiment of the present invention, a binder includes a solid solution obtained by dissolving Ca components in SrAl₂O₄ therein. At this time, when SrAl₂O₄ is α-SrAl₂O₄, a crystallite diameter of the solid solution is from 40 nm to 75 nm; or when SrAl₂O₄ is β-SrAl₂O₄, a crystallite diameter of the solid solution is from 35 nm to 70 nm.

A binder, which includes a solid solution having a crystallite diameter in the above-described predetermined range, has a higher melting point than that of alumina cement (major chemical component: CaO.Al₂O₃) in the conventional technology, and has excellent high temperature stability when it reacts with water so as to form the hardened body. In addition, in particular, when the crystallite diameter is in the above-described predetermined range, by using the present binder, an appropriate operation time can be secured when manufacturing monolithic refractories. Furthermore, since hardening rate is improved compared to that in the conventional technology, corrosion resistance and strength can be improved. As a result, the present binder can be used for a wide range of uses as a binder.

However, in order to facilitate the effects, it is preferable that an amount of the solid solution be 10 mass % or higher in the binder. In addition, the upper limit of the amount may be 100 mass %. The composition of a balance in the binder is typically Al₂O₃, and also includes examples of SiO₂, TiO₂, Fe₂O₃, MgO, BaO, or the like. With regard to how they can intrude into the binders of the present invention, in the case of Al₂O₃, it may be intentionally added in order to impart a high level of fireproofness thereto. In the case of other components, a case in which they have already been included in raw materials to be used or a case in which the binders are contaminated from a crushing apparatus, a transportation apparatus, a firing apparatus, or the like of binder raw materials or products during the manufacturing process can be considered. In addition, a solid solution according to the following embodiment can be included in the binder as a mixture.

In a binder for monolithic refractories according to a second embodiment of the present invention, a solid solution, obtained by dissolving SrO as Sr components in CaO.Al₂O₃, is blended into a binder including the solid solution according to the first embodiment obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm, or into a binder including the solid solution according to the first embodiment obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm. In this case, a crystallite diameter of the solid solution obtained by dissolving SrO in CaO.Al₂O₃ is from 25 nm to 60 nm.

With regard to the existence form of these solid solutions in the binder, they are not present as a single solid solution obtained by being solidified with each other but are present as independent solid solutions. The binder is present in the form of a mixture.

A content ratio of the solid solution obtained by dissolving SrO in CaO.Al₂O₃ included in the binder is not limited. However, in order to facilitate the effects thereof, it is preferable that an amount of a mixture of the solid solution in the binder be 10 mass % or higher. In addition, the upper limit of the amount may be 100 mass %. If there is a balance in the binder, the composition of the balance is typically Al₂O₃, and also includes examples of SiO₂, TiO₂, Fe₂O₃, MgO, BaO, or the like. With regard to how they can intrude into the binders of the present invention, as in the case of the first embodiment, Al₂O₃ may be intentionally added in order to impart a high level of fireproofness thereto. In the case of other components, a case in which they have already been included in raw materials to be used or a case in which the binders are contaminated from a crushing apparatus, a transportation apparatus, a firing apparatus, or the like of binder raw materials or products during the manufacturing process can be considered.

The solid solution obtained by dissolving SrO in CaO.Al₂O₃ is hydraulic, has a higher melting point than that of CaO.Al₂O₃ of alumina cement in the conventional technology, and has excellent high temperature stability when it reacts with water so as to form the hardened body. Therefore, it is possible to obtain a greater effect than that with a binder in the conventional technology. In addition, the solid solution obtained by dissolving SrO in CaO.Al₂O₃ is more preferable because a crystallite diameter of the solid solution is from 25 nm to 60 nm and thus an appropriate operation time and hardening rate can be obtained.

According to a third embodiment of the present invention, both of the solid solution according to the first embodiment obtained by dissolving Ca components in α-SrAl₂O₄ which has a crystallite diameter in the predetermined range and the solid solution according to the first embodiment obtained by dissolving Ca components in β-SrAl₂O₄ which has a crystallite diameter in the predetermined range, are included in a binder. The third embodiment is different from the first embodiment in that both of the solutions are included, not either of them. This binder may further include the solid solution according to the second embodiment obtained by dissolving Sr components in CaO.Al₂O₃. With regard to the existence form of these solid solutions in the binder, they are not present as a single solid solution obtained by being solidified with each other but are present as independent solid solutions. The binder is present in the form of a mixture. In addition, according to the third embodiment, as in the cases of the first embodiment and the second embodiment, it is possible to obtain a greater effect than that with a binder in the conventional technology.

A ratio of two or three kinds of solid solutions as a mixture in the binder is not particularly limited. However, in order to facilitate the effects thereof, it is preferable that a total amount of a mixture of these solid solutions in the binder be 10 mass % or higher. In addition, the upper limit of the amount may be 100 mass %. The composition of a balance in the binder is typically Al₂O₃, and also includes examples of SiO₂, TiO₂, Fe₂O₃, MgO, BaO, or the like. With regard to how they can intrude into the binders of the present invention, as in the cases of the first and second embodiments, Al₂O₃ may be intentionally added in order to impart a high level of fireproofness thereto. In the case of other components, a case in which they have already been included in raw materials to be used or a case in which the binders are contaminated from a crushing apparatus, a transportation apparatus, a firing apparatus, or the like of binder raw materials or products during the manufacturing process can be considered.

By performing the maintenance and optimization of the selection and manufacturing processes of industrially used raw materials, an amount of SiO₂, TiO₂, Fe₂O₃, MgO, BaO, and the like, which are impurities in the binders of the first to third embodiment, can be reduced to a level with no influence on the effects of the present invention. The amount is preferably 12 mass % or less and more preferably 5 mass % or less with respect to the total mass of the binders of the present invention in the total amount of chemical components, which is the converted amount of the oxides of the respective chemical components. If the amount is more than 12 mass %, there are cases in which performance degradation, such as degradation of the strength developing property and corrosion resistance of monolithic refractories using the binders, occurs.

In addition, when the amount of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO is 12 mass % or less, the cured strength of monolithic refractories may increase. The reason is considered that minerals containing these components generate amorphous materials and ions are liable to be eluted when it reacts with water. Strength increases greatly when the amount is 5 mass % or less and the increase continues until 12 mass %. However, when the amount exceeds 12 mass %, conversely, there are cases in which strength is reduced maybe because the minerals containing the components generate crystalline materials having a low solubility in water. In addition, there are cases where high temperature corrosion resistance is degraded maybe because a melting point of impurities is lowered.

Furthermore, the present inventors also reviewed a case where no Ca components are included in a solid solution of SrAl₂O₄ in comparison, but found that there were differences in the functions of a binder, from the case where Ca components are included as in the present invention. Therefore, in order to study the functions of the binders, an ion elution test was conducted to compare reaction processes with water of both of the cases to each other. As a result, in a case where the composition of a solid solution is represented by Ca_(x)Sr_(1-x)Al₂O₄, it was found that the initial amount of ions eluted of a solid solution in which X=0 and no Ca components were included was extremely greater than that of a solid solution in which Ca components was included (for example, X=0.15). Therefore, in the case where no Ca components were included, the elution speed of ions was extremely fast. After a saturated solubility was reached, hydration products were precipitated in a supersaturated solution. A cross-linked structure was generated between particles so as to contribute to binding and strength development for hardening.

In detail, the rate of Sr ions eluted from the SrAl₂O₄ composition, in which no Ca components were included, into mixing water and the rate of Sr and Ca ions eluted from the above-described various solid solutions according to the present invention were compared. For the comparison, 200 g of a specimen was fed into 400 g of distilled water and stirred for a predetermined period of time using a magnetic stirrer, and then the solution was extracted and analyzed with inductively-coupled plasma (ICP) optical emission spectrometry, thereby measuring the amount of elements in the solution. The elements in the solution were presumed to be present in a variety of ion states. As a result of comparing the amounts for the same stirring time, it was quantitatively found that the rate of Sr ions eluted from SrAl₂O₄, in which no Ca components were included, into mixing water was greater than the rate of Sr and Ca ions eluted from the above-described various solid solutions according to the present invention.

Therefore, when the solid solution in which X=0 is used for the binder for monolithic refractories, agglomeration of materials occurs easily due to a large amount of ions eluted. As a result, the necessary time for hardening is shortened and an amount of monolithic refractories to be constructed is large. For example, when an hour or longer is necessary for construction, there is a possibility of problems such as the hardening of a material during mixing and during pouring. To suppress this, it is necessary that a large amount of additives which have an effect of sequestering initially eluted ions, that is, a large amount of boric acid, borax, sodium gluconate, silicofluorides, or the like be added as a hardening retardant compared to the case where Ca components are included (for example, X=0.15). Still, when the function of the hardening retardant which suppresses ion elution does not work, hardening proceeds immediately.

Therefore, when a long period of time is necessary for construction, for example, in furnace facilities where there is a large amount to be constructed, it was found that the case where Ca components are included is preferable from the viewpoint of more stable construction.

Since a binder is usually used in the powder state, it is preferable that the above-described solid solutions according to the present invention be present in the powder state in the binders.

In addition, crystallite diameters of all the solid solutions can be calculated by the Scherrer method after obtaining the full-width at half maximum from the diffraction peak obtained by powder X-ray diffractometry. The solid solutions according to the present invention have a characteristic that a diffraction line thereof changes depending on the blending ratio of Ca and Sr. The respective crystallite diameters can be calculated by obtaining the full-width at half maximum: from the diffraction peak of (−2 1 1) plane with 2θ of about 28.4° in the case of the solid solution obtained by dissolving Ca components in α-SrAl₂O₄; from the diffraction peak of (1 0 2) plane with 2θ of about 29.5° in the case of the solid solution obtained by dissolving Ca components in β-SrAl₂O₄; and from the diffraction peak of (1 2 3) plane with 2θ of about 30.0° in the case of the solid solution obtained by dissolving Sr components in CaAl₂O₄.

In detail, in the various solid solutions, for which a variety of raw materials are prepared and synthesized by a firing method, when a batch furnace is used, samples are taken from various places, such as the surface, interior, or the like of a fired body; and when a continuous furnace such as a rotary kiln is used, samples are taken on a predetermined time interval basis (for example, on a minute basis) to obtain average evaluation samples. Then, the samples (for example, n=10) are sampled, divided, and then crushed by a crusher so that the 50% average diameter becomes 10 μm or less. The samples are measured using a powder X-ray diffractometer (for example, JDX-3500, trade name, manufactured by JEOL Ltd.), and it is possible to calculate the crystallite diameter using JADE 6, a powder X-ray diffraction pattern analyzing software.

The measurement of crystallite diameters using an X-ray diffractometer may be performed under the conditions of an X-ray source of CuKα, a tube voltage of 40 kV, a tube current of 300 mA, a step angle of 0.02°, and a spectroscopy with a measurement condition of monochromator of 2θ from 15° to 40°. With regard to the X-ray diffractometer-derived full-width at half maximum used for the analysis of crystallite diameter, it is possible to use values obtained by measuring silicon powder specimens with the same diffractometer under the same conditions and then obtaining the full-width at half maximum curves.

Next, a manufacturing method of the binders according to the present invention will be described.

In the manufacture of the solid solution obtained by dissolving Ca components in α-SrAl₂O₄, the solid solution obtained by dissolving Ca components in β-SrAl₂O₄, and the solid solution obtained by dissolving Sr components in CaAl₂O₄, these can be respectively manufactured according to the firing temperature by changing the blending ratio of starting materials so as to be a predetermined molar ratio.

As the starting materials, any raw materials can be used as long as CaO, SrO, and Al₂O₃ are used as the major chemical components. However, since there is a possibility that CaO and SrO may be hydrated in the atmosphere, CaCO₃, SrCO₃, and Al₂O₃ are preferably used. The kind of raw materials will be described in detail.

The blending ratio of CaO:SrO:Al₂O₃ is set by weighing and blending the raw materials so that Ca_(x)Sr_(1-x)Al₂O₄ has a predetermined X in terms of molar ratio.

As the crystal phase obtained after firing the mixture at, for example 1450° C., when X is equal to 1.0, CaAl₂O₄ is obtained; when X is from about 0.8 to 0.9, the solid solution obtained by dissolving Sr components in CaAl₂O₄ is obtained; when X is from about 0.5 to 0.7, a mixture of the solid solution obtained by dissolving Sr components in CaAl₂O₄ and the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ is obtained; when X is from about 0.3 to 0.4, the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ is obtained; when X is from about 0.1 to 0.2, a mixture of the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ and the solid solution obtained by dissolving Ca components in α-SrAl₂O₄ is obtained; and when X is more than 0 and equal to or less than 0.1, the solid solution obtained by dissolving Ca components in α-SrAl₂O₄ is obtained.

At this time, along with the increase in the molar ratio of Sr, the lattice constants of a-axis, b-axis, and c-axis increase. This is because of, for example, the ionic radii of Ca and Sr. Referring to the ionic radii during pouring, the ionic radius of Ca is 0.099 nm and the ionic radius of Sr is 0.113 nm and Sr has a larger ionic radius. It is presumed that, due to the substitution with Sr having a larger ionic radius, the lattice expands and the lattice spacing expands.

Therefore, these crystal phases can be identified using the powder X-ray diffractometry (XRD) and can be respectively obtained while checking a desired solid solution and a mixture thereof. As the device, for example, a RAD-B system equipped with a curved crystal monochromator (manufactured by Rigaku Corporation) can be used. The XRD measurement is performed under the conditions of an anticathode of Cu (CuKα), 2θ from 15° to 70°, a tube voltage of 40 kV, a tube current of 20 mA, a scan step of 0.010 deg, a scan speed of 4°/min, a divergence slit of ½ deg, a receiving slit of 0.15 nm, and a scattering slit of ½ deg. However, the conditions for the XRD measurement are not limited thereto. When the crystal phases are precisely measured, it is preferable that silicon, aluminum, and magnesium be used as primary standards and an internal standard method be used.

In addition, the solid solutions and the mixtures of the solid solutions may be further blended to obtain a desired mixture of the solid solutions.

In addition, as a method of making a crystallite diameter a predetermined size, in cases where the crystallite diameter of the solid solution obtained by dissolving Ca components in α-SrAl₂O₄ is made to be from 40 nm to 75 nm; where the crystallite diameter of the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ is made to be from 35 nm to 70 nm; and where the crystallite diameter of the solid solution obtained by dissolving Sr components in CaAl₂O₄ is made to be from 25 nm to 60 nm, firing is performed at a temperature of preferably from 1300° C. to 1600° C. and more preferably from 1400° C. to 1500° C. using a firing apparatus, such as an electric furnace, a reverberating furnace, an open-hearth furnace, a shaft furnace, a shuttle kiln, or a rotary kiln.

When the firing temperature is lower than 1300° C., unreacted raw materials are liable to remain and there are cases in which the amount of a target solid solution generated is reduced. In addition, when the firing temperature is higher than 1600° C., there are cases in which the crystal of a solid solution is excessively grown, the crystallite diameter thereof becomes large beyond the predetermined range, and therefore the strength developing property deteriorates. At a temperature of from 1400° C. to 1500° C., it is possible to shorten the firing time to obtain a predetermined crystallite diameter and it becomes difficult for the crystallite diameter to be excessively increased due to excessive firing. Therefore, this temperature range is preferable.

The time period of firing may be adjusted so that a target crystallite diameter is obtained at each temperature, and, for example, is from about 1 hour to 24 hours at 1400° C. and from about 0.5 hours to 12 hours at 1500° C. When firing is performed for longer than 24 hours at 1400° C. and for longer than 12 hours at 1500° C., the crystallite diameter of a solid solution becomes too large beyond the predetermined range of crystallite diameter. Therefore, the hardened strength after a short-term curing time deteriorates, which is not preferable. It is more preferable that the firing temperature and the firing time be 1400 to 1500° C. and 1 to 5 hours.

The above-described appropriate temperature and firing time varies to some extent depending on the specification of a furnace, such as the volume or heating capacity. Therefore, it is preferable to check phases generated in specimens after firing through X-ray diffraction measurement and check whether or not a solid solution having a target crystallite diameter range has been generated for the manufacture, from the viewpoint of reliably obtaining a desired solid solution.

In all of the first to third embodiments, it is preferable that Al₂O₃ be blended thereinto in a case in which there is a demand for a further increase in the strength or refractoriness of hardened bodies when the solid solutions react with water so as to form the hardened body. The preferable amount of the solid solutions in the binder is from 10 mass % to 60 mass %, and the preferable amount of Al₂O₃ blended thereinto is from 40 mass % to 90 mass %.

With the amount of the solid solutions of less than 10 mass %, depending on the chemical components or particle size distribution of the aggregates in monolithic refractories, there are cases in which it becomes difficult to develop a sufficient hardened strength.

On the other hand, with the amount of the solid solutions of higher than 60 mass %, depending on the chemical components or particle size distribution of the aggregates in monolithic refractories, there are cases in which the hardening rate is too fast and it becomes difficult to secure a sufficient usable life for construction.

In addition, if the amount of Al₂O₃ in the binder is 40 mass % or higher, the strength or refractoriness of hardened bodies increases sufficiently, which is preferable. However, if the amount of Al₂O₃ to be blended thereinto is more than 90 mass %, the amount of the solid solutions becomes relatively small, and thus it may become difficult to be uniformly hardened. Therefore, the amount of Al₂O₃ to be blended thereinto is preferably 90 mass % or less.

Next, a monolithic refractory used for the binder for monolithic refractories according to the present invention will be described. In the present invention, the blending ratio of the binder and refractory aggregates in a monolithic refractory is not particularly specified, and it has been confirmed that, even with an arbitrary blending ratio, the effects of the present invention can be obtained.

However, in a case in which the binder for monolithic refractories of the present invention is used to manufacture actual monolithic refractories, with regard to the blending ratio of the binder and refractory aggregates, it is suggested that the amount of the binder is preferably from 0.3 mass % to 20 mass %, and further preferably from 0.5 mass % to 12 mass % with respect to 100 mass % of the total amount of the binder and refractory aggregates.

This is because, with an amount of less than 0.3 mass %, there are cases in which binding is not sufficient and therefore the strength is not sufficient even after the binder has been hardened. In addition, it is because, with an amount of more than 20 mass %, there are cases in which volume change, or the like generated during the hydration or dehydration process of the binder adversely affects the entire monolithic refractories, and therefore cracking, or the like occurs.

As the refractory aggregates of monolithic refractories, fused alumina, fused bauxite, sintered alumina, calcined alumina, fused mullite, synthesized mullite, melted silica, fused zirconia, fused zirconia mullite, zircon, magnesia clinker, fused magnesia, fused magnesite-chrome, sintered spinel, fused spinel, silicon nitride, silicon carbide, squamation graphite, earthy graphite, sillimanite, kyanite, andalusite, agalmatolite, shale, dolomite clinker, silica rock, clay, chamotte, lime, chrome, melted quartz, calcium aluminate, calcium silicate, or silica flower can be used. They may be used alone or in combination of two or more kinds thereof.

In a case in which the binder of the present invention is used as a binder for monolithic refractories, the amount of water or water-containing solvent used for construction is not particularly specified. However, the amount is dependent on the particle size distribution of aggregates or the type and amount of dispersants, and therefore it is preferable that the amount is roughly from about 2 mass % to 10 mass % with respect to the refractory aggregates in outer percentage.

This is because, if the amount is less than 2 mass %, it becomes difficult to harden the binder. In addition, it is because, if the amount is more than 10 mass %, the amount relating to the formation of hardened structures becomes relatively large, and volume change, or the like during hardening reactions becomes liable to adversely affect the quality of refractories.

In addition, if the binder of the present invention is used as a binder for monolithic refractories, in order to appropriately control the rate of the hydration and hardening reactions according to the atmospheric temperature or humidity, it is preferable to add a dispersant or a hardening adjuster.

As the dispersant, carbonates, such as sodium carbonate, sodium hydrogen carbonate, or the like; oxycarboxylic acids, such as citric acid, sodium citrate, tartaric acid, sodium tartrate acid, or the like; polyacrylic acid or methacrylic acid and salts thereof; condensed phosphates, such as sodium tripolyphosphate or sodium hexametaphosphate, or the like, and/or alkali metals thereof; alkaline-earth metal salts, or the like are mainly used.

As the hardening adjuster, a hardening retardant or a hardening accelerator can be used. As the hardening retardant, it is possible to use boric acid, borax, sodium gluconate, silicofluorides, or the like. On the other hand, as the hardening accelerator, it is possible to use lithium salts, such as lithium carbonate or the like; slaked lime or the like; and aluminates or the like.

In addition, a method also can be used that increases the ventilation rate of materials by adding an explosion preventer, such as an organic fiber, such as vinylon, or the like, metallic aluminum powder, aluminum lactate, or the like.

Furthermore, it is also possible to add ultrafine powder in order to achieve improvement in the flow property, a filling property or sinterability. Examples of the ultrafine powder include inorganic fine powder with a particle diameter of from about 0.01 μm to 100 μm, such as silica fume, colloidal silica, well-sinterable alumina, amorphous silica, zirconia, silicon carbide, silicon nitride, chrome oxide, titanium oxide, or the like.

In a case in which a basic aggregate, such as magnesia, or the like, is blended thereinto, there is a possibility of the generation of cracking caused by hydration swelling of magnesia. In order to suppress such a phenomenon, it is preferable to add a highly surface-active additive, such as fumed silica.

Furthermore, since the monolithic refractories of the present invention are used to manufacture dense hardened bodies, during mixing with water, it is possible to use chemical admixtures, such as a water reducing agent, such as a polycarbonate-based water reducing agent, a lignin-based water reducing agent, or the like, a high performance water reducing agent, a high performance AE water reducing agent, or the like. The type and amount added of the above chemical admixtures can be properly selected according to the type or amount of refractory aggregates to be blended thereinto and conditions, such as the construction temperature, or the like.

As raw materials used for manufacturing the solid solution obtained by dissolving Ca components in α-SrAl₂O₄, the solid solution obtained by dissolving Ca components in β-SrAl₂O₄, and the solid solution obtained by dissolving Sr components in CaAl₂O₄, which are the binders for monolithic refractories according to the present invention, lime stone (mainly CaCO₃), calcined lime (mainly CaO), purified alumina (α-Al₂O₃, Al(OH)₃) or bauxite (a raw material of Al₂O₃), strontianite (SrCO₃) or celestite (SrSO₄) are preferably used. Before firing, it is preferable to crush the raw material with a crusher so as to have a 50% average diameter (median diameter) of from about 0.5 μm to 15 μm. This is because, if the raw material includes particles coarser than the above, there are cases in which a large number of unreacted parts remain or a composition other than the solid solutions according to the present invention is partially generated, and therefore there are cases in which the intrinsic effects of the present invention become difficult to develop.

As the composition other than the solid solutions according to the present invention, there are cases in which, if alumina components are rich in the raw material, a solid solution such as Ca_(x)Sr_(1-x)Al₄O₇ is generated, and if CaO components and SrO components are rich in the raw material, a solid solution such as (Ca_(x)Sr_(1-x))₁₂Al₁₄O₃₃ or (Ca_(x)Sr_(1-x))₃Al₂O₆ is generated. However, if the raw materials are prepared, crushed, and blended as described above so as to obtain the target solid solution according to the present invention, the amount of the above generation is small and has less effect on the binder characteristics.

Furthermore, the raw material to be used is preferably a high purity material with 98 mass % or more of a total amount of CaO, Al₂O₃ and SrO in the raw material. Impurities included in bauxite, strontianite or celestite, such as SiO₂, TiO₂, MgO, Fe₂O₃, or the like, have a possibility of degrading high temperature properties, and it is preferable to suppress these to an extremely small amount.

Since the particle size of solid solution powder in the binders affects hydration reaction or hardening rate, it is preferable to control particles to be from about 1 μm to 20 μm by a crusher after firing for manufacturing a solid solution. The particle size is a measurement result by a particle size analyzer used for a laser diffractometry, a laser scattering method, a sedimentation balance method, or the like and indicates the 50% average diameter. The raw material can be uniformly blended using a mixer, such as an Eirich mixer, a rotary drum, a cone blender, a V-shape blender, an omni mixer, a nauta mixer, a pan-type mixer, or the like.

As the crusher, it is possible to use an industrial crusher, such as an oscillating mill, a tube mill, a ball mill, a roller mill, a jet mill or the like.

The binders, in which from 10 mass % to 60 mass % of the solid solutions according to the first to third embodiment are included and from 40 mass % to 90 mass % of Al₂O₃ is blended, can be manufactured by blending α-alumina powder into the various solid solutions obtained by the above-described method.

α-alumina powder refers to high purity alumina including 90 mass % or more of Al₂O₃, and generally alumina is manufactured by the Bayer process. In this method, firstly, bauxite is washed in a hot solution of sodium hydroxide (NaOH) at 250° C. In this process, alumina is transformed to aluminum hydroxide (Al(OH₃)) and dissolved by a reaction shown in the following formula (1). Al₂O₃+2OH⁻+3H₂O→2[Al(OH)₄]⁻  (1)

At this time, other chemical components in the bauxite are not dissolved and can be removed through filtering as solid impurities. Subsequently, if the solution is cooled, the dissolved aluminum hydroxide is precipitated as a white fluffy solid. If the solid is subjected to a firing treatment at 1050° C. or higher using a rotary kiln, or the like, dehydration shown in the following formula (2) occurs and therefore alumina is generated. 2Al(OH)₃→Al₂O₃+3H₂O  (2)

Since binders are highly dependent on the specific surface area of α-Al₂O₃ blended into the binders in terms of the flow property, the BET specific surface area of α-Al₂O₃ is preferably from about 0.1 m²/g to 20 m²/g.

α-Al₂O₃ can be blended thereinto in a state of being made into fine particles or by blending and crushing it with the various solid solutions.

When α-Al₂O₃ to be blended into the binder is crushed and then blended, it is preferable that refinement be performed so that the 50% average diameter be from about 0.3 μm to 10 μm. In addition, fine alumina powder with the above-described particle diameter can be blended. In addition, when the components of the solid solutions and α-Al₂O₃ are crushed and blended, it is preferable to set crushing conditions so that the 50% average diameter of α-Al₂O₃ be in the same range.

When the 50% average diameter of α-Al₂O₃ is in the above-described range, sinterability with respect to aggregates to be blended into binders or monolithic refractories is improved and a dense structure having excellent corrosion resistance can be obtained.

In addition, the higher the purity of Al₂O₃, the superior the refractoriness. Therefore, the purity of α-Al₂O₃ is preferably 95 mass % or higher and more preferably 99 mass % or higher.

This α-Al₂O₃ is uniformly blended with hydraulic components by blending it in the binder in advance. When the resultant is blended into a monolithic refractory, the hydraulic components can be more uniformly blended and it is possible to obtain a structure of refractory having excellent strength developing property and corrosion resistance of hardened bodies.

In the present invention, the manner in which α-Al₂O₃ is blended with the binder and crushed is preferable since α-Al₂O₃ is uniformly blended into the binder composition and therefore the microstructure of the hardened bodies is liable to become uniform when used for monolithic refractories, and this manner has a tendency of improving performance, such as corrosion resistance, or the like.

In addition, in the monolithic refractory according to the present invention, a construction method of refractories used for the lining or repair of furnaces may be the same as a general construction method of monolithic refractories. However, particularly when an aggregate including an ultrafine alumina powder with a particle diameter of from 0.8 nm to 1 μm and the binders according to the present invention are blended and mixed for construction, binding is further improved due to the synergistic effect with the binders according to the present invention. As a result, a favorable strength developing property is developed within a short period of time, construction efficiency is improved, corrosion resistance with respect to slag and molten iron is further improved, and the effect of service life expansion of furnaces can be more strongly exhibited. Therefore, the above-described manner is preferable.

It is preferable that the blending ratio of the ultrafine alumina powder with a particle diameter of 1 μm or less in the monolithic refractory (other than moisture) be from 2 mass % to 70 mass %

EXAMPLES

Hereinafter, the present invention will be described in detail with examples, but the present invention is not limited to the examples.

In the following examples, as the raw materials, CaCO₃ with a purity of 99 mass % (manufactured by Ube Material Co., Ltd.), SrCO₃ with a purity of 98 mass % (manufactured by Sakai Chemical Industry Co., Ltd.), and high purity α-alumina with a purity of 99 mass % (manufactured by Nippon Light Metal Co., Ltd.) were used.

Each of the raw materials was weighed with scales so as to have the chemical compositions in the following tables, and then blended and crushed with a mortar. 15 mass % of water was added to the blended and crushed raw materials in outer percentage, was granulated into spherical pellets, were fed into an alumina container, and then subjected to a heating treatment at the maximum temperature in the air atmosphere using an electric furnace (with a furnace volume of 130 L) while changing the holding time thereof. After that, the resultant were cooled to room temperature and placed in the air, and then crushed with a batch type ball mill so as to obtain various solid solutions and binders shown in the examples.

Furthermore, with regard to examples in which α-Al₂O₃ is blended, high purity α-alumina (manufactured by Nippon Light Metal Co., Ltd.) was added to the obtained solid solutions and binders so as to obtain a predetermined chemical component.

In addition, in order to study the effects of impurities, barium oxide was used which was obtained by heating at 1400° C. a variety of reagents with a purity of 99 mass %, such as silicon oxide, titanium oxide, magnesium oxide and ferric oxide and a barium carbonate reagent with a purity of 99%. The raw materials were blended according to the contents of the respective following tables to prepare the binders in the same manner described above.

8 mass % of the binder, 92 mass % of refractory aggregates (50 mass % of sintered alumina with a particle size by sieving of 1 μm or lower, 43 mass % of fused alumina with a particle size of from 75 μm to 5 mm, 6 mass % of magnesia, 0.8 mass % of silica flower, and 0.15 mass % of vinylon fiber), and 0.05 mass % of boric acid powder were blended for 1 minute with an omni mixer, and, furthermore, 6.8 mass % of water was added to 100 mass % of the mixture thereof in a constant temperature room of 20° C. and then blended and mixed with a mortar mixer for 3 minutes, thereby obtaining monolithic refractory specimens.

In order to evaluate the operability of the prepared monolithic refractory specimens, the flow test was carried out according to JIS R2521, “Physical testing methods of aluminous cement for refractories” to measure spreading diameters of samples immediately after mixing and 2 hours after the start of blending, in which the samples were subjected to falling motion 15 times.

The flexural strength after curing was measured according to JIS 82553, “Testing method for crushing strength and modulus of rupture of castable refractories” after the monolithic refractory specimens were poured into a 40×40×160 mm mold form and then cured in a constant temperature room at 20° C. for a predetermined time. In addition, the curing time was set to 6, 12, and 24 hours after the start of blending of monolithic refractories.

In addition, the monolithic refractory specimens were cured in a constant temperature room at 20° C. for a predetermined time to manufacture hardened bodies of the refractories and provide specimens for a test for the evaluation of corrosion resistance with respect to slag at a high temperature.

The rotary corrosion method was used for the evaluation of corrosion resistance with respect to slag at a high temperature. Specimens (refractory 1) cut out into the shape as in FIG. 1 were manufactured, and, as shown in FIG. 2, 8 pieces of the refractory 1 were lined and embedded in a rotary furnace. The size thereof was a=67 mm, b=41 mm, c=48 mm, and d=114 mm. In addition, a cylindrical protection plate 2 (with a diameter of about 150 mmφ) was embedded on the inner side on which 8 pieces of the refractory 1 were lined.

As shown in FIG. 3, the embedded refractory 1 was installed in the rotary furnace, and the temperature was increased by the burning of a burner 3 from the inside of the rotary furnace while rotating the refractory 1. As the burning gas, a gas with a volume ratio of 1 LPG to 5 oxygen was used. Further, the reference number 4 indicates slag, and the reference number 5 indicates a filling material.

The wear amount of each specimen was obtained from the average value obtained by measuring the remaining dimensions (which are the thicknesses of a non-oxidation layer in the case of the thicknesses of a decarburized layer) at 5 points every 20 mm and calculating the difference from the initial thickness (48 mm). The composition of the slag 4 includes 50.5 mass % of CaO, 16.8 mass % of SiO₂, 7 mass % of MgO, 2 mass % of Al₂O₃, 3.5 mass % of MnO, and 20.2 mass % of FeO, and, with the test temperature of 1600° C. and 1 charge of 25 minutes, 500 g of the slag 4 was subjected to 1 charge of the test for a replacement, and the test was performed for a total of 6 charges for 2 hours 30 minutes. The old charge of the slag 4 was replaced with a new charge of the slag 4 by tilting a horizontal type drum.

[1] Example relating to a binder for monolithic refractories including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a solid solution for which all the components of a binder had been controlled so as to solidify Ca components in α-SrAl₂O₄ and firing conditions had been set so that a crystallite diameter thereof was a value in the tables in Examples 1 to 8 and Reference Examples 1 to 6; monolithic refractories manufactured with binders including a solid solution for which all the components of a binder had been controlled so as to solidify Ca components in β-SrAl₂O₄ and firing conditions had been set so that a crystallite diameter thereof was a value in the tables in Examples 9 to 16 and Reference Examples 7 to 12; monolithic refractories manufactured with binders including no Sr components in Comparative Examples 1 to 3; and monolithic refractories manufactured with binders including no Ca components in Reference Examples 13 to 16. Tables 1 to 3 show the composition of the raw materials of the binder, the crystallite diameter of the solid solution, the firing conditions, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the examples.

In addition, when the monolithic refractory manufactured with the binder including no Ca components was used in Reference Example 15, the test results were obtained after 0.3 mass % of boric acid powder to be blended into the monolithic refractory was added with respect to the mass of castable in outer percentage so as to obtain a predetermined flow property 2 hours after the start of mixing.

TABLE 1 Reference Example Example Example Example Reference Reference Example 1 1 2 3 4 Example 2 Example 3 Raw materials of solid CaCO₃ 2 2 2 2 2 2 2 solution obtained by SrCO₃ 57 57 57 57 57 57 57 dissolving Ca components α-Al₂O₄ 41 41 41 41 41 41 41 in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 30 38 47 59 76 81 86 obtained by dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- 1400° C.- 1500° C.- temperature-holding time) 2 hr 2 hr 2 hr 2 hr 1 hr 48 hr 48 hr 15 tap-flow value After mixing 187 181 176 179 173 162 165 (mm) After 2 hours 102 118 129 131 134 135 131 Bending strength after 1.8 1.6 1.5 1.3 1.1 0.7 0.6 curing of 6 hours (MPa) Bending strength after 1.9 1.8 1.8 1.7 1.6 1 0.9 curing of 12 hours (MPa) Bending strength after 2.2 2.2 2.1 2.1 2.1 1.5 1.3 curing of 24 hours (MPa) Wear amount in rotary 6.4 6.5 6.6 6.4 6.6 6.9 6.9 corrosion test (mm) Reference Example Example Example Example Example 4 5 6 7 8 Raw materials of solid CaCO₃ 6.2 6.2 6.2 6.2 6.2 solution obtained by SrCO₃ 52.2 52.2 52.2 52.2 52.2 dissolving Ca components α-Al₂O₄ 41.6 41.6 41.6 41.6 41.6 in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.15 0.15 0.15 Crystallite diameter of solid solution 28 36 44 56 73 obtained by dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- temperature-holding time) 2 hr 2 hr 2 hr 2 hr 1 hr 15 tap-flow value After mixing 182 179 179 175 171 (mm) After 2 hours 105 122 126 135 136 Bending strength after 1.5 1.6 1.5 1.3 1.2 curing of 6 hours (MPa) Bending strength after 2 2 1.9 1.7 1.5 curing of 12 hours (MPa) Bending strength after 2.5 2.4 2.4 2.3 2 curing of 24 hours (MPa) Wear amount in rotary 6.6 6.4 6.5 6.4 6.5 corrosion test (mm)

TABLE 2 Reference Reference Reference Example Example Example Example Example 5 Example 6 Example 7 9 10 11 12 Raw materials of solid CaCO₃ 6.2 6.2 12.7 12.7 12.7 12.7 12.7 solution obtained by SrCO₃ 52.2 52.2 44.2 44.2 44.2 44.2 44.2 dissolving Ca components α-Al₂O₃ 41.6 41.6 43.1 43.1 43.1 43.1 43.1 in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 77 81 31 35 47 54 70 obtained by dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1400° C.- 1500° C.- 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- temperature-holding time) 48 hr 48 hr 2 hr 2 hr 2 hr 2 hr 1 hr 15 tap-flow value After mixing 171 165 176 172 172 169 164 (mm) After 2 hours 142 135 107 123 125 123 129 Bending strength after 0.6 0.5 1.5 1.5 1.3 1.2 1 curing of 6 hours (MPa) Bending strength after 1 0.8 1.9 2 1.9 1.7 1.5 curing of 12 hours (MPa) Bending strength after 1.4 1.3 2.1 2.2 2.3 2.4 2.3 curing of 24 hours (MPa) Wear amount in rotary 6.6 6.9 6.6 6.4 6.5 6.4 6.5 corrosion test (mm) Reference Reference Reference Example Example Example 8 Example 9 Example 10 13 14 Raw materials of solid CaCO₃ 12.7 12.7 24.6 24.6 24.6 solution obtained by SrCO₃ 44.2 44.2 30.1 30.1 30.1 dissolving Ca components α-Al₂O₃ 43.1 43.1 45.2 45.2 45.2 in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.55 0.55 0.55 Crystallite diameter of solid solution 74 79 24 36 45 obtained by dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1400° C.- 1500° C.- 1200° C.- 1300° C.- 1400° C.- temperature-holding time) 48 hr 48 hr 2 hr 2 hr 2 hr 15 tap-flow value After mixing 165 160 186 175 174 (mm) After 2 hours 134 131 109 124 127 Bending strength after 0.6 0.5 1.4 1.3 1.3 curing of 6 hours (MPa) Bending strength after 0.9 0.8 1.8 1.8 1.7 curing of 12 hours (MPa) Bending strength after 1.7 1.7 2 2.4 2.4 curing of 24 hours (MPa) Wear amount in rotary 6.6 6.5 6.6 6.6 6.4 corrosion test (mm)

TABLE 3 Example Example Reference Reference Reference Reference 15 16 Example 11 Example 12 Example 13 Example 14 Raw materials of solid solution CaCO₃ 24.6 24.6 24.6 24.6 0 0 obtained by dissolving Ca SrCO₃ 30.1 30.1 30.1 30.1 59.4 59.4 components in α- or β- α-Al₂O₃ 45.2 45.2 45.2 45.2 40.6 40.6 SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.55 0.55 0.55 0.55 0 0 Crystallite diameter of solid solution obtained by 53 65 72 76 41 64 dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1500° C.- 1600° C.- 1400° C.- 1500° C.- 1300° C.- 1500° C.- temperature-holding time) 2 hr 1 hr 48 hr 48 hr 2 hr 2 hr 15 tap-flow value After mixing 171 168 163 159 188 183 (mm) After 2 hours 126 133 131 134 Solidified Solidified Bending strength after 1.2 1.1 0.5 0.5 — — curing of 6 hours (MPa) Bending strength after 1.6 1.5 0.9 0.8 — — curing of 12 hours (MPa) Bending strength after 2.3 2.4 1.8 1.5 — — curing of 24 hours (MPa) Wear amount in rotary 6.5 6.5 6.6 6.8 — — corrosion test (mm) Reference Reference Comparative Comparative Comparative Example 15 Example 16 Example 1 Example 2 Example 3 Raw materials of solid solution CaCO₃ 0 0 49.5 49.5 49.5 obtained by dissolving Ca SrCO₃ 59.4 59.4 0 0 0 components in α- or β- α-Al₂O₃ 40.6 40.6 50.5 50.5 50.5 SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0 0 1 1 1 Crystallite diameter of solid solution obtained by 64 76 38 48 49 dissolving Ca components in SrAl₂O₄ (nm) Firing conditions (maximum 1500° C.- 1600° C.- 1300° C.- 1500° C.- 1600° C.- temperature-holding time) 2 hr 2 hr 2 hr 2 hr 2 hr 15 tap-flow value After mixing 172 177 181 172 173 (mm) After 2 hours 121 Solidified 122 148 153 Bending strength after 1.4 — 0.6 0.6 0.5 curing of 6 hours (MPa) Bending strength after 1.8 — 1.1 1.1 1 curing of 12 hours (MPa) Bending strength after 2.3 — 1.7 1.6 1.7 curing of 24 hours (MPa) Wear amount in rotary 6.3 — 8.4 8.2 8.4 corrosion test (mm)

The evaluation results are as shown in Tables 1 to 3. In Examples 1 to 16, the flow values suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 1 to 16 can be applied to furnaces with a large volume or the like. Furthermore, Examples 1 to 16 show larger values than Comparative Examples 1 to 3 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 1 to 16 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 1 to 16 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 1 to 16 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In Reference Examples 1, 4, 7, and 10 in which the crystallite diameters of the solid solution obtained by dissolving Ca components in α-SrAl₂O₄ and the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ are less than the range of the present invention and in Reference Examples 13, 14, and 16 in which the binder including no Ca components was used, a large amount of deterioration in the flow property after 2 hours or the hardening of the monolithic refractories occurred, and therefore it has been confirmed that it is difficult for Reference Examples 1, 4, 7, and 10 and Reference Examples 13, 14, and 16 be applied to furnaces with a large volume or the like. As described in Reference Example 15, by increasing the amount of boric acid powder as the hardening retardant added, the flow property after 2 hours can be secured. However, it is necessary that the amount of the hardening retardant added be increased to a large degree, which leads to a rise in manufacturing costs. In addition, in Reference Examples 2, 3, 5, 6, 8, 9, 11, and 12 in which the crystallite diameters are more than the range of the present invention, it has been confirmed that, compared to the case where the crystallite diameter is in the range of the present invention, the strength after curing deteriorates, it is difficult for a frame to be removed early, and the risk of explosion increases due to insufficient strength when the monolithic refractories are dried.

From these test results, it has been clarified that, by using the binder including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[2] Examples relating to a binder for monolithic refractories including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, into which Al₂O₃ is blended

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.05, into which α-Al₂O₃ was blended with a predetermined ratio, in Examples 17 to 21; monolithic refractories manufactured with binders including a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30, into which α-Al₂O₃ was blended with a predetermined ratio, in Examples 22 to 26; and monolithic refractories manufactured with binders obtained by blending raw materials so that the composition of a binder is CaAl₂O₄ and blending the resultant and α-Al₂O₃ with a predetermined ratio in Comparative Examples 4 to 6. Tables 4 and 5 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the solid solutions, CaAl₂O₄, and α-Al₂O₃, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. All of the solid solutions and the binders were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture.

TABLE 4 Example Example Example Example Example Example Example Example 3 17 18 19 20 21 11 22 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.3 0.3 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 54 54 dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving 100 62 60 40 10 8 100 62 Ca components in SrAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) 0 0 0 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 38 40 60 90 92 0 38 15 tap-flow value After mixing 179 180 175 169 163 158 169 172 (mm) After 2 hours 131 133 135 134 132 138 123 128 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.1 1 0.9 1.2 1.1 Bending strength after curing of 12 hours (MPa) 1.7 1.6 1.6 1.4 1.2 1.2 1.7 1.5 Bending strength after curing of 24 hours (MPa) 2.1 2.2 2.1 1.9 1.7 1.6 2.4 2.2 Wear amount in rotary corrosion test (mm) 6.4 6.1 6 5.7 5.3 5.3 6.4 6.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 5 Compar- Compar- Example Example Example Example Comparative Comparative ative ative 23 24 25 26 Example 2 Example 4 Example 5 Example 6 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 1 1 1 1 Crystallite diameter of solid solution obtained by 54 54 54 54 — — — — dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 60 40 10 8 — — — — dissolving Ca components in SrAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) 0 0 0 0 100 60 40 10 Blending ratio of α-Al₂O₃ (mass %)*¹ 40 60 90 92 0 40 60 90 15 tap-flow value After mixing 172 168 163 161 172 170 167 159 (mm) After 2 hours 131 130 132 135 148 133 135 141 Bending strength after curing of 6 hours (MPa) 1.1 1 0.8 0.8 0.6 0.5 0.5 0.3 Bending strength after curing of 12 hours (MPa) 1.5 1.4 1.2 1.2 1.1 1.1 0.9 0.6 Bending strength after curing of 24 hours (MPa) 2.2 1.9 1.6 1.5 1.6 1.6 1.5 1.1 Wear amount in rotary corrosion test (mm) 6.1 5.7 5.3 5.2 8.2 8 7.9 7.6 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Tables 4 and 5. In Examples 17 to 26, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 17 to 26 can be applied to furnaces with a large volume or the like. Furthermore, Examples 17 to 26 show larger values than Comparative Examples 1 to 6 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 17 to 26 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 17 to 26 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 17 to 26 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, in Examples 17 to 26, it is possible to further decrease the wear amount in the rotary corrosion test using slag, compared to Examples 3 and 11 including no Al₂O₃, since Examples 17 to 26 include Al₂O₃, which clarifies that Examples 17 to 26 are superior in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, into which Al₂O₃ is blended, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[3] Examples relating to a binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄; and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a crystallite diameter of the solid solution is from 25 nm to 60 nm.

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of a solid solution for which all the components of a binder had been controlled so as to solidify Ca components in α-SrAl₂O₄ and a solid solution for which all the components of a binder had been controlled so as to solidify Sr components in CaAl₂O₄, in which firing conditions had been set so that a crystallite diameter thereof was a value in the tables in Examples 27 to 37 and Reference Examples 17 to 19; and monolithic refractories manufactured with binders including a mixture of a solid solution for which all the components of a binder had been controlled so as to solidify Ca components in β-SrAl₂O₄ and a solid solution for which all the components of a binder had been controlled so as to solidify Sr components in CaAl₂O₄, in which firing conditions had been set so that a crystallite diameter thereof was a value in the tables in Examples 38 to 48 and Reference Examples 20 to 22. The solid solution obtained by dissolving Ca components in α-SrAl₂O₄ and the solid solution obtained by dissolving Ca components in β-SrAl₂O₄ were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture. Tables 6 to 8 show the composition of the raw materials, the firing conditions, the crystallite diameters of the solid solutions, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples.

TABLE 6 Reference Example Example Example Example Example 17 27 28 29 30 Raw materials of solid solution obtained by dissolving CaCO₃ 2 2 2 2 2 Ca components in α- or β-SrAl₂O₄ (mass %) SrCO₃ 57 57 57 57 57 α-Al₂O₃ 41 41 41 41 41 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in SrAl₂O₄ (mass %) Raw materials of solid solution obtained by dissolving CaCO₃ 32.3 32.3 32.3 32.3 32.3 Sr components in CaAl₂O₄ (mass %) SrCO₃ 20.6 20.6 20.6 20.6 20.6 α-Al₂O₃ 47 47 47 47 47 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.7 0.7 0.7 0.7 0.7 Crystallite diameter of solid solution obtained by 24 29 42 51 59 dissolving Sr components in CaAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- 2 hr 2 hr 2 hr 2 hr 1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Sr components in CaAl₂O₄ (mass %) 15 tap-flow value (mm) After mixing 184 182 183 176 174 After 2 hours 102 119 124 136 132 Bending strength after curing of 6 hours (MPa) 1.6 1.5 1.3 1.3 1.2 Bending strength after curing of 12 hours (MPa) 1.9 1.8 1.7 1.6 1.6 Bending strength after curing of 24 hours (MPa) 2.1 2.2 2.3 2.3 2.3 Wear amount in rotary corrosion test (mm) 6.5 6.6 6.8 6.6 6.7 Example Reference Reference Example Example 31 Example 18 Example 19 32 33 Raw materials of solid solution obtained by dissolving CaCO₃ 2 2 2 2 2 Ca components in α- or β-SrAl₂O₄ (mass %) SrCO₃ 57 57 57 57 57 α-Al₂O₃ 41 41 41 41 41 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in SrAl₂O₄ (mass %) Raw materials of solid solution obtained by dissolving CaCO₃ 32.3 32.3 46.5 46.5 46.5 Sr components in CaAl₂O₄ (mass %) SrCO₃ 20.6 20.6 3.7 3.7 3.7 α-Al₂O₃ 47 47 49.9 49.9 49.9 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.7 0.7 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 63 68 21 25 39 dissolving Sr components in CaAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1400° C.- 1500° C.- 1200° C.- 1300° C.- 1400° C.- 48 hr 48 hr 2 hr 2 hr 2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Sr components in CaAl₂O₄ (mass %) 15 tap-flow value (mm) After mixing 171 172 181 180 179 After 2 hours 124 131 104 121 134 Bending strength after curing of 6 hours (MPa) 1 0.6 1.6 1.6 1.4 Bending strength after curing of 12 hours (MPa) 1.5 1.1 2 1.9 1.9 Bending strength after curing of 24 hours (MPa) 2.4 2.1 2.2 2.3 2.1 Wear amount in rotary corrosion test (mm) 6.6 6.7 6.7 6.6 6.5

TABLE 7 Example Example Example Example Reference Example Example Example Example 34 35 36 37 Example 20 38 39 40 41 Raw materials of solid CaCO₃ 2 2 2 2 2 12.7 12.7 12.7 12.7 solution obtained by SrCO₃ 57 57 57 57 57 44.2 44.2 44.2 44.2 dissolving Ca α-Al₂O₃ 41 41 41 41 41 43.1 43.1 43.1 43.1 components in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 59 59 59 59 54 54 54 54 54 obtained by dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained 50 50 50 50 50 50 50 50 50 by dissolving Ca components in SrAl₂O₄ (mass %) Raw materials of solid CaCO₃ 46.5 46.5 46.5 46.5 32.3 32.3 32.3 32.3 32.3 solution obtained by SrCO₃ 3.7 3.7 3.7 3.7 20.6 20.6 20.6 20.6 20.6 dissolving Sr components α-Al₂O₃ 49.9 49.9 49.9 49.9 47 47 47 47 47 in CaAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.7 0.7 0.7 0.7 0.7 Crystallite diameter of solid solution 50 55 59 65 24 29 42 51 59 obtained by dissolving Sr components in CaAl₂O₄ (nm) Firing conditions (maximum 1500° C.- 1600° C.- 1400° C.- 1500° C.- 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- temperature-holding time) 2 hr 1 hr 48 hr 48 hr 2 hr 2 hr 2 hr 2 hr 1 hr Blending ratio of solid solution obtained 50 50 50 50 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (mass %) 15 tap-flow value (mm) After mixing 181 176 172 167 178 180 176 172 167 After 2 hours 135 137 134 134 103 117 122 132 132 Bending strength after curing of 1.3 1.2 1.1 1.1 1.5 1.4 1.3 1.2 1.1 6 hours (MPa) Bending strength after curing of 1.6 1.6 1.5 1.4 1.8 1.7 1.7 1.6 1.6 12 hours (MPa) Bending strength after curing of 2.4 2.5 2.5 2.4 2.4 2.3 2.4 2.3 2.4 24 hours (MPa) Wear amount in rotary corrosion 6.7 6.7 6.8 6.9 6.6 6.6 6.7 6.6 6.7 test (mm)

TABLE 8 Reference Reference Example Example Example Example Example Example Example Example Example 42 21 22 43 44 45 46 47 48 Raw materials of solid CaCO₃ 12.7 12.7 12.7 12.7 12.7 12.7 12.7 12.7 12.7 solution obtained by SrCO₃ 44.2 44.2 44.2 44.2 44.2 44.2 44.2 44.2 44.2 dissolving Ca components α-Al₂O₃ 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1 43.1 in α- or β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained 50 50 50 50 50 50 50 50 50 by dissolving Ca components in SrAl₂O₄ (mass %) Raw materials of solid CaCO₃ 32.3 32.3 46.5 46.5 46.5 46.5 46.5 46.5 46.5 solution obtained SrCO₃ 20.6 20.6 3.7 3.7 3.7 3.7 3.7 3.7 3.7 by dissolving Sr α-Al₂O₃ 47 47 49.9 49.9 49.9 49.9 49.9 49.9 49.9 components in CaAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.7 0.7 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 63 68 21 25 39 50 55 59 65 obtained by dissolving Sr components in CaAl₂O₄ (nm) Firing conditions (maximum 1400° C.- 1500° C.- 1200° C.- 1300° C.- 1400° C.- 1500° C.- 1600° C.- 1400° C.- 1500° C.- temperature-holding time) 48 hr 48 hr 2 hr 2 hr 2 hr 2 hr 1 hr 48 hr 48 hr Blending ratio of solid solution obtained 50 50 50 50 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (mass %) 15 tap-flow value After mixing 162 163 185 176 172 172 173 169 167 (mm) After 2 hours 135 131 103 118 124 128 131 134 134 Bending strength after curing of 0.8 0.6 1.6 1.4 1.3 1.1 1.1 1 1 6 hours (MPa) Bending strength after curing of 1.4 1 1.9 1.8 1.8 1.6 1.4 1.5 1.4 12 hours (MPa) Bending strength after curing of 2 1.8 2.1 2.4 2.4 2.5 2.5 2.5 2.4 24 hours (MPa) Wear amount in rotary corrosion 6.7 6.9 6.8 6.7 6.6 6.7 6.6 6.9 6.9 test (mm)

The evaluation results are as shown in Tables 6 to 8. In Examples 27 to 48, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 27 to 48 can be applied to furnaces with a large volume or the like. Furthermore, Examples 27 to 48 show larger values than Comparative Examples 1 to 3 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 27 to 48 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of Comparative Examples 1 to 3, and therefore it has been confirmed that Examples 27 to 48 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples 1 to 3, Examples 27 to 48 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In Reference Examples 17, 19, 20, and 22 in which the crystallite diameter of the solid solution obtained by dissolving Sr components in CaAl₂O₄ is less than the range of the present invention, a large amount of deterioration in the flow property after 2 hours occurred, and therefore it has been confirmed that it is difficult for Reference Examples 17, 19, 20, and 22 to be applied to furnaces with a large volume or the like. In addition, in Reference Examples 18 and 21 in which the crystallite diameters are more than the range of the present invention, it has been confirmed that, compared to the case where the crystallite diameter is in the range of the present invention, the flexural strength after curing deteriorates, it is difficult for a frame to be removed early, and the risk of explosion increases due to insufficient strength when the monolithic refractories are dried.

From these test results, it has been clarified that, by using the binder including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm; and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a crystallite diameter of the solid solution is from 25 nm to 60 nm, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[4] Examples relating to a binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ or β-SrAl₂O₄ and a solid solution obtained by dissolving Sr components in CaAl₂O₄, into which Al₂O₃ is blended

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.05 and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.95, into which α-Al₂O₃ was blended with a predetermined ratio, in Examples 49 to 53; and monolithic refractories manufactured with binders obtained including a mixture of a solid solution obtained by dissolving Ca components in 13-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30 and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.95, into which α-Al₂O₃ was blended with a predetermined ratio, in Examples 54 to 58. Table 9 shows the compositions of the solid solutions, the crystallite diameters, the blending ratio of the solid solutions and α-Al₂O₃, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. All of the solid solutions were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture.

TABLE 9 Example Example Example Example Example Example 34 49 50 51 52 53 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by dissolving 59 59 59 59 59 59 Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 50 31 30 20 5 4 components in SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by dissolving 50 50 50 50 50 50 Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Sr 50 31 30 20 5 4 components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 0 38 40 60 90 92 15 tap-flow value After mixing 181 174 173 170 166 165 (mm) After 2 hours 135 133 131 138 134 131 Bending strength after curing of 6 hours (MPa) 1.3 1.1 1.1 1.1 1 0.8 Bending strength after curing of 12 hours (MPa) 1.6 1.5 1.5 1.4 1.2 1.2 Bending strength after curing of 24 hours (MPa) 2.4 2.1 2.1 2 1.9 1.8 Wear amount in rotary corrosion test (mm) 6.7 6.2 6.2 5.8 5.4 5.3 Example Example Example Example Example Example 45 54 55 56 57 58 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by dissolving 54 54 54 54 54 54 Ca components in SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 50 31 30 20 5 4 components in SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by dissolving 50 50 50 50 50 50 Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Sr 50 31 30 20 5 4 components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 0 38 40 60 90 92 15 tap-flow value After mixing 172 170 168 166 166 165 (mm) After 2 hours 128 130 132 135 134 131 Bending strength after curing of 6 hours (MPa) 1.1 1 1 0.9 0.8 0.8 Bending strength after curing of 12 hours (MPa) 1.6 1.4 1.4 1.4 1.3 1.2 Bending strength after curing of 24 hours (MPa) 2.5 2.3 2.2 2 1.9 1.9 Wear amount in rotary corrosion test (mm) 6.7 6.3 6.3 5.7 5.5 5.4 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Table 9. In Examples 49 to 58, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 49 to 58 can be applied to furnaces with a large volume or the like. Furthermore, Examples 49 to 58 show larger values than Comparative Examples 1 to 6 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 49 to 58 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 49 to 58 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 49 to 58 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, in Examples 49 to 58, it is possible to further decrease the wear amount in the rotary corrosion test using slag, compared to Examples 34 and 45 including no Al₂O₃, since Examples 49 to 58 include Al₂O₃, which clarifies that Examples 49 to 58 are superior in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm or a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm; and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a crystallite diameter of the solid solution is from 25 nm to 60 nm, into which Al₂O₃ is blended, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[5] Examples relating to a binder for monolithic refractories including a mixture of both of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of both of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.05 or 0.15 and a crystallite diameter of the solid solution is from 40 nm to 75 nm and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30 or 0.55 and a crystallite diameter of the solid solution is from 35 nm to 70 nm in Examples 59 to 94. Tables 10 to 13 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the firing conditions, the blending ratio of the solid solutions, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. In each solid solution, firing conditions had been set so that a crystallite diameter thereof was a value in the tables.

TABLE 10 Example 59 Example 60 Example 61 Example 62 Example 63 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 38 38 38 38 38 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.55 0.55 Crystallite diameter of solid solution obtained by 35 54 70 36 53 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by 50 50 50 50 50 dissolving Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 184 181 182 179 178 (mm) After 2 hours 119 122 121 125 125 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.4 1.4 1.4 Bending strength after curing of 12 hours (MPa) 2 1.9 1.9 1.9 1.8 Bending strength after curing of 24 hours (MPa) 2.4 2.3 2.4 2.3 2.3 Wear amount in rotary corrosion test (mm) 6.4 6.4 6.5 6.5 6.4 Example 64 Example 65 Example 66 Example 67 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 38 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.55 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 65 35 54 70 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr Blending ratio of solid solution obtained by 50 50 50 50 dissolving Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 176 173 171 170 (mm) After 2 hours 124 124 127 124 Bending strength after curing of 6 hours (MPa) 1.3 1.4 1.3 1.1 Bending strength after curing of 12 hours (MPa) 1.7 1.8 1.7 1.6 Bending strength after curing of 24 hours (MPa) 2.3 2.4 2.3 2.4 Wear amount in rotary corrosion test (mm) 6.5 6.4 6.6 6.6

TABLE 11 Example 68 Example 69 Example 70 Example 71 Example 72 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 76 76 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1500° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.55 0.55 0.55 0.3 0.3 Crystallite diameter of solid solution obtained by 36 53 65 35 54 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 172 171 168 166 165 (mm) After 2 hours 129 128 131 125 134 Bending strength after curing of 6 hours (MPa) 1.2 1.2 1.1 1.3 1.1 Bending strength after curing of 12 hours (MPa) 1.7 1.7 1.6 1.8 1.6 Bending strength after curing of 24 hours (MPa) 2.2 2.3 2.4 2.1 2.3 Wear amount in rotary corrosion test (mm) 6.5 6.6 6.4 6.6 6.6 Example 73 Example 74 Example 75 Example 76 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 76 76 76 76 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1600° C.-1 hr 1600° C.-1 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.55 0.55 0.55 Crystallite diameter of solid solution obtained by 70 36 53 65 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 161 168 165 161 (mm) After 2 hours 134 127 132 136 Bending strength after curing of 6 hours (MPa) 1 1.2 1.1 1 Bending strength after curing of 12 hours (MPa) 1.5 1.6 1.5 1.5 Bending strength after curing of 24 hours (MPa) 2.3 2.2 2.4 2.3 Wear amount in rotary corrosion test (mm) 6.7 6.6 6.7 6.5

TABLE 12 Example 77 Example 78 Example 79 Example 80 Example 81 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.15 0.15 0.15 Crystallite diameter of solid solution obtained by 36 36 36 36 36 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr 1300° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in α-SrAl₂O₄(mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.55 0.55 Crystallite diameter of solid solution obtained by 35 54 70 36 53 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 180 181 173 182 175 (mm) After 2 hours 119 124 127 120 122 Bending strength after curing of 6 hours (MPa) 1.4 1.4 1.2 1.3 1.2 Bending strength after curing of 12 hours (MPa) 1.9 1.8 1.7 1.8 1.7 Bending strength after curing of 24 hours (MPa) 2.4 2.3 2.4 2.2 2.3 Wear amount in rotary corrosion test (mm) 6.6 6.7 6.7 6.8 6.6 Example 82 Example 83 Example 84 Example 85 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.15 0.15 Crystallite diameter of solid solution obtained by 36 56 56 56 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in α-SrAl₂O₄(mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.55 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 65 35 54 70 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 169 179 169 167 (mm) After 2 hours 132 123 127 127 Bending strength after curing of 6 hours (MPa) 1.1 1.3 1.3 1.1 Bending strength after curing of 12 hours (MPa) 1.6 1.7 1.7 1.6 Bending strength after curing of 24 hours (MPa) 2.4 2.3 2.4 2.3 Wear amount in rotary corrosion test (mm) 6.5 6.7 6.6 6.6

TABLE 13 Example 86 Example 87 Example 88 Example 89 Example 90 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.15 0.15 0.15 Crystallite diameter of solid solution obtained by 56 56 56 73 73 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1500° C.-2 hr 1500° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.55 0.55 0.55 0.3 0.3 Crystallite diameter of solid solution obtained by 36 53 65 35 54 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 177 169 164 179 170 (mm) After 2 hours 121 126 130 125 131 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.1 1.3 1.2 Bending strength after curing of 12 hours (MPa) 1.8 1.7 1.5 1.6 1.6 Bending strength after curing of 24 hours (MPa) 2.2 2.4 2.3 2.1 2.3 Wear amount in rotary corrosion test (mm) 6.8 6.5 6.9 6.8 6.6 Example 91 Example 92 Example 93 Example 94 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.15 0.15 0.15 0.15 Crystallite diameter of solid solution obtained by 73 73 73 73 dissolving Ca components in α-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1600° C.-1 hr 1600° C.-1 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.55 0.55 0.55 Crystallite diameter of solid solution obtained by 70 36 53 65 dissolving Ca components in β-SrAl₂O₄ (nm) Firing conditions (maximum temperature-holding time) 1600° C.-1 hr 1300° C.-2 hr 1500° C.-2 hr 1600° C.-1 hr Blending ratio of solid solution obtained by dissolving 50 50 50 50 Ca components in β-SrAl₂O₄ (mass %) 15 tap-flow value After mixing 169 177 173 169 (mm) After 2 hours 134 124 130 136 Bending strength after curing of 6 hours (MPa) 1.1 1.3 1.2 1.1 Bending strength after curing of 12 hours (MPa) 1.6 1.8 1.7 1.6 Bending strength after curing of 24 hours (MPa) 2.5 2.3 2.4 2.3 Wear amount in rotary corrosion test (mm) 6.7 6.5 6.8 6.6

The evaluation results are as shown in Tables 10 to 13. In Examples 59 to 94, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 59 to 94 can be applied to furnaces with a large volume or the like. Furthermore, Examples 59 to 94 show larger values than Comparative Examples 1 to 3 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 59 to 94 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 59 to 94 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples 1 to 3, Examples 59 to 94 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a mixture of both of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[6] Examples relating to a binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄, into which Al₂O₃ is blended

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.05 and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30, into which α-Al₂O₃ was blended with a predetermined ratio, in Examples 95 to 99. Table 14 shows the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the solid solutions, the binder, and α-Al₂O₃, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. All of the solid solutions were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture.

TABLE 14 Example Example 66 95 Example 96 Example 97 Example 98 Example 99 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 50 31 30 20 5 4 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained 54 54 54 54 54 54 by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 50 31 30 20 5 4 dissolving Ca components in β-SrAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 0 38 40 60 90 92 15 tap-flow value (mm) After mixing 171 173 175 175 169 165 After 2 hours 127 130 132 135 132 127 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.1 1 0.9 Bending strength after curing of 12 hours (MPa) 1.7 1.6 1.6 1.5 1.4 1.4 Bending strength after curing of 24 hours (MPa) 2.3 2.4 2.2 2.3 2.1 2 Wear amount in rotary corrosion test (mm) 6.6 6.2 6.1 5.6 5.2 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Table 14. In Examples 95 to 99, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 95 to 99 can be applied to furnaces with a large volume or the like. Furthermore, Examples 95 to 99 show larger values than Comparative Examples 1 to 6 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 95 to 99 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 95 to 99 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 95 to 99 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, in Examples 95 to 99, it is possible to further decrease the wear amount in the rotary corrosion test using slag, compared to Example 66 including no Al₂O₃, since Examples 95 to 99 include Al₂O₃, which clarifies that Examples 95 to 99 are superior in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm and a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, into which Al₂O₃ is blended, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[7] Examples relating to a binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄, and a solid solution obtained by dissolving Sr components in CaAl₂O₄

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄Al₂O₄ is 0.05, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30, and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.95 in Examples 100 to 104. Table 15 shows the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the solid solutions, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. All of the solid solutions were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture.

TABLE 15 Example 100 Example 101 Example 102 Example 103 Example 104 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 35 30 20 10 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 35 30 20 10 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 30 40 60 80 dissolving Sr components in CaAl₂O₄ (mass %) 15 tap-flow value (mm) After mixing 167 165 166 163 163 After 2 hours 129 133 131 134 137 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.1 0.9 Bending strength after curing of 12 hours (MPa) 1.6 1.6 1.5 1.5 1.3 Bending strength after curing of 24 hours (MPa) 2.4 2.5 2.5 2.5 2.5 Wear amount in rotary corrosion test (mm) 6.7 6.6 6.7 6.8 7 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Table 15. In Examples 100 to 104, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 100 to 104 can be applied to furnaces with a large volume or the like. Furthermore, Examples 100 to 104 show larger values than Comparative Examples 1 to 6 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 100 to 104 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 100 to 104 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 100 to 104 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a crystallite diameter of the solid solution is from 25 nm to 60 nm, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[8] Examples relating to a binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄, and a solid solution obtained by dissolving Sr components in CaAl₂O₄, into which Al₂O₃ is blended

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which an X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.05, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which an X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.30, and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which an X value of Ca_(x)Sr_(1-x)Al₂O₄ is 0.95, into which α-Al₂O₃ is blended, in Examples 105 to 109. Table 16 shows the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the solid solutions and α-Al₂O₃, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. All of the solid solutions were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture.

TABLE 16 Example 101 Example 105 Example 106 Example 107 Example 108 Example 109 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄(nm) Blending ratio of solid solution obtained by 35 21.7 21 14 3.5 2.8 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained 54 54 54 54 54 54 by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 35 21.7 21 14 3.5 2.8 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 30 18.6 18 12 3 2.4 dissolving Sr components in CaAl₂O₄ (mass %) Mixing ratio of α-Al₂O₃ (mass %)*¹ 0 38 40 60 90 92 15 tap-flow value (mm) After mixing 166 169 167 166 162 160 After 2 hours 131 134 133 137 133 131 Bending strength after curing of 6 hours (MPa) 1.2 1.1 1.1 1 0.7 0.7 Bending strength after curing of 12 hours (MPa) 1.5 1.5 1.5 1.4 1.2 1.1 Bending strength after curing of 24 hours (MPa) 2.5 2.3 2.2 2 1.9 1.8 Wear amount in rotary corrosion test (mm) 6.7 6.3 6.3 5.9 5.4 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Table 16. In Examples 105 to 109, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 105 to 109 can be applied to furnaces with a large volume or the like. Furthermore, Examples 105 to 109 show larger values than Comparative Examples 1 to 6 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 105 to 109 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 105 to 109 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 105 to 109 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, in Examples 105 to 109 it is possible to further decrease the wear amount in the rotary corrosion test using slag, compared to Example 101 including no Al₂O₃, since Examples 105 to 109 include Al₂O₃, which clarifies that Examples 105 to 109 are superior in terms of slag resistance at a high temperature.

From these test results, it has been clarified that, by using the binder for monolithic refractories including a mixture of a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 40 nm to 75 nm, a solid solution obtained by dissolving Ca components in β-SrAl₂O₄ in which a crystallite diameter of the solid solution is from 35 nm to 70 nm, and a solid solution obtained by dissolving Sr components in CaAl₂O₄ in which a crystallite diameter of the solid solution is from 25 nm to 60 nm, into which Al₂O₃ is blended, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[9] Examples relating to a binder for monolithic refractories according to the present invention including one kind or two or more kinds selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO in which an amount thereof is 12 mass % or less

Characteristics were evaluated using monolithic refractories manufactured with binders including a solid solution obtained by blending various combinations of one kind or two or more kinds selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO in Examples 110 to 221 in order to verify the effects of the contamination amount of the raw materials to be used and inevitable impurities generated during the manufacturing process. Characteristics were evaluated using monolithic refractories manufactured with binders having amounts of a variety of contamination components, which were out of the range of the invention, blended thereinto in Comparative Examples 7 to 30.

Characteristics were evaluated using monolithic refractories manufactured with binders including a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in α-SrAl₂O₄ or β-SrAl₂O₄ in Examples 110 to 137 and Comparative Examples 7 to 14; monolithic refractories manufactured with binders including a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in α-SrAl₂O₄ or β-SrAl₂O₄, into which Al₂O₃ was blended, in Examples 138 to 149; monolithic refractories manufactured with binders including a mixture of two or three kinds selected from a group consisting of a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in α-SrAl₂O₄, a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in β-SrAl₂O₄, and a solid solution for which the chemical components of a binder had been controlled to solidify Sr components in CaAl₂O₄ in Examples 150 to 197 and Comparative Examples 15 to 30; and monolithic refractories manufactured with binders including a mixture of two or three kinds selected from a group consisting of a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in α-SrAl₂O₄, a solid solution for which the chemical components of a binder had been controlled to solidify Ca components in β-SrAl₂O₄, and a solid solution for which the chemical components of a binder had been controlled to solidify Sr components in CaAl₂O₄, into which Al₂O₃ was blended, in Examples 198 to 221.

Tables 17 to 43 show the chemical composition and chemical components, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of Examples and Comparative Examples. All of the solid solutions were subjected to firing for 2 hours at the maximum temperature of 1500° C. for manufacture. In addition, the chemical components of the manufactured binders were measured using X-ray fluorescence analysis (“ZSX-Primus II”, a scanning X-ray fluorescence analyzer manufactured by Rigaku Corporation).

TABLE 17 Example 110 Example 111 Example 112 Example 113 Example 114 Raw materials of solid CaCO₃ 2 2 1.9 1.9 1.9 solution A obtained by SrCO₃ 55.6 55.6 54.5 54.5 54.5 dissolving Ca α-Al₂O₃ 40.4 40.4 39.6 39.6 39.6 components in α-SrAl₂O₄ SiO₂ 2 0 4 0 0 including various impurity MgO 0 2 0 4 0 components (mass %) BaO 0 0 0 0 4 TiO₂ 0 0 0 0 0 Fe₂O₃ 0 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 58 59 56 61 56 Blending ratio of solid solution A (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution B obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in β-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution B (nm) — — — — — Blending ratio of solid solution B (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 1.4 1.3 1.3 1.2 1.3 of chemical SrO 47 47.1 46 45.9 45.9 components of Al₂O₃ 49.1 49 47.9 48 47.9 binder (mass %) Total amount of SiO₂, 2.4 2.5 4.7 4.8 4.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 181 180 183 182 185 value (mm) After 2 hours 133 134 130 129 123 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.5 1.4 1.4 Bending strength after curing of 12 hours (MPa) 1.9 2 1.9 1.8 2 Bending strength after curing of 24 hours (MPa) 2.2 2.2 2.3 2 2.3 Wear amount in rotary corrosion test/mm 6.3 6.2 6.5 6.2 6.2 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 18 Example 115 Example 116 Example 117 Example 118 Example 119 Raw materials of solid CaCO₃ 1.9 1.9 1.9 1.8 1.8 solution A obtained by SrCO₃ 54.5 54.5 53.9 51.7 51.7 dissolving Ca α-Al₂O₃ 39.6 39.6 39.2 37.5 37.5 components in α-SrAl₂O₄ SiO₂ 0 0 1 9 0 including various impurity MgO 0 0 1 0 9 components (mass %) BaO 0 0 1 0 0 TiO₂ 4 0 1 0 0 Fe₂O₃ 0 4 1 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 61 56 58 55 63 Blending ratio of solid solution A (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution B obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in β-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution B (nm) — — — — — Blending ratio of solid solution B (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 1.3 1.3 1.3 1.2 1.3 of chemical SrO 45.9 45.9 45.4 43.1 43.1 components of Al₂O₃ 47.9 48 47.4 44.9 45 binder (mass %) Total amount of SiO₂, 4.8 4.7 5.8 10.7 10.5 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 180 183 182 179 180 value (mm) After 2 hours 133 130 134 136 135 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.4 1.4 1.5 Bending strength after curing of 12 hours (MPa) 1.9 1.9 1.8 1.8 1.8 Bending strength after curing of 24 hours (MPa) 2.2 2.4 2.2 2 2.1 Wear amount in rotary corrosion test/mm 6.4 6.6 6.5 6.7 6.1 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 19 Comparative Example 120 Example 121 Example 122 Example 123 Example 7 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.8 1.8 solution A obtained by SrCO₃ 51.7 51.7 51.7 51.1 49.9 dissolving Ca α-Al₂O₃ 37.5 37.5 37.5 37.1 36.3 components in α-SrAl₂O₄ SiO₂ 0 0 0 2 12 including various impurity MgO 0 0 0 2 0 components (mass %) BaO 9 0 0 2 0 TiO₂ 0 9 0 2 0 Fe₂O₃ 0 0 9 2 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 60 55 54 57 54 Blending ratio of solid solution A (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution B obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in β-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution B (nm) — — — — — Blending ratio of solid solution B (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 1.3 1.2 1.2 1.2 1.2 of chemical SrO 43.1 43.1 43.2 42.3 41.3 components of Al₂O₃ 45 44.9 44.7 44.4 43.1 binder (mass %) Total amount of SiO₂, 10.6 10.7 10.8 12 14.3 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 175 183 186 184 177 value (mm) After 2 hours 121 136 122 126 141 Bending strength after curing of 6 hours (MPa) 1.6 1.3 1.5 1.3 0.9 Bending strength after curing of 12 hours (MPa) 2 1.7 1.9 1.8 1.4 Bending strength after curing of 24 hours (MPa) 2.3 2 2.1 2.1 1.9 Wear amount in rotary corrosion test/mm 6.2 6.6 6.9 6.3 7.5 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 20 Comparative Comparative Comparative Example 8 Example 9 Example 10 Example 124 Example 125 Raw materials of solid CaCO₃ 1.8 1.7 1.6 — — solution A obtained by SrCO₃ 49.9 48.3 45.4 — — dissolving Ca α-Al₂O₃ 36.3 35 33 — — components in α-SrAl₂O₄ SiO₂ 0 3 4 — — including various impurity MgO 12 3 4 — — components (mass %) BaO 0 3 4 — — TiO₂ 0 3 4 — — Fe₂O₃ 0 3 4 — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 — — Crystallite diameter of solid solution A (nm) 62 60 52 — — Blending ratio of solid solution A (mass %) 100 100 100 0 0 Raw materials of solid CaCO₃ — — — 12.5 12.5 solution B obtained by SrCO₃ — — — 43 43 dissolving Ca α-Al₂O₃ — — — 42.5 42.5 components in β-SrAl₂O₄ SiO₂ — — — 2 0 including various impurity MgO — — — 0 2 components (mass %) BaO — — — 0 0 TiO₂ — — — 0 0 Fe₂O₃ — — — 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — 0.3 0.3 Crystallite diameter of solid solution B (nm) — — — 54 55 Blending ratio of solid solution B (mass %) 0 0 0 100 100 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 1.3 1.1 0.9 8.5 8.6 of chemical SrO 41.3 39.8 37.2 36.7 36.7 components of Al₂O₃ 43.2 41.5 38.7 52.2 52.2 binder (mass %) Total amount of SiO₂, 14.1 17.5 23.1 2.5 2.4 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 177 180 172 175 174 value (mm) After 2 hours 134 125 118 126 128 Bending strength after curing of 6 hours (MPa) 0.6 1 0.7 1.4 1.3 Bending strength after curing of 12 hours (MPa) 1 1.4 1.1 1.8 1.8 Bending strength after curing of 24 hours (MPa) 1.5 1.8 1.7 2.4 2.3 Wear amount in rotary corrosion test/mm 6.6 7.6 8.2 6.4 6.3 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 21 Example 126 Example 127 Example 128 Example 129 Example 130 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 12.3 12.3 12.3 12.3 12.3 solution B obtained by SrCO₃ 42.2 42.2 42.2 42.2 42.2 dissolving Ca α-Al₂O₃ 41.5 41.5 41.5 41.5 41.5 components in β-SrAl₂O₄ SiO₂ 4 0 0 0 0 including various impurity MgO 0 4 0 0 0 components (mass %) BaO 0 0 4 0 0 TiO₂ 0 0 0 4 0 Fe₂O₃ 0 0 0 0 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 54 56 56 53 53 Blending ratio of solid solution B (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 8.4 8.4 8.4 8.4 8.3 of chemical SrO 35.9 35.9 35.9 35.9 35.9 components of Al₂O₃ 50.8 50.8 50.9 50.8 50.8 binder (mass %) Total amount of SiO₂, 4.9 4.9 4.7 4.9 5 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 177 173 171 170 170 value (mm) After 2 hours 126 129 125 136 131 Bending strength after curing of 6 hours (MPa) 1.4 1.4 1.4 1.3 1.5 Bending strength after curing of 12 hours (MPa) 1.9 1.9 1.9 1.8 1.9 Bending strength after curing of 24 hours (MPa) 2.3 2.4 2.3 2.3 2.4 Wear amount in rotary corrosion test/mm 6.5 6.3 6.3 6.4 6.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 22 Example 131 Example 132 Example 133 Example 134 Example 135 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 12.1 11.6 11.6 11.6 11.6 solution B obtained by SrCO₃ 41.7 40 40 40 40 dissolving Ca α-Al₂O₃ 41.2 39.4 39.4 39.4 39.4 components in β-SrAl₂O₄ SiO₂ 1 9 0 0 0 including various impurity MgO 1 0 9 0 0 components (mass %) BaO 1 0 0 9 0 TiO₂ 1 0 0 0 9 Fe₂O₃ 1 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 54 52 58 58 52 Blending ratio of solid solution B (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 8.1 7.8 8 7.8 7.9 of chemical SrO 35.4 33.6 33.8 33.6 33.6 components of Al₂O₃ 50.2 47.6 47.5 47.6 47.8 binder (mass %) Total amount of SiO₂, 6.3 10.8 10.7 10.8 10.6 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 174 174 172 168 173 value (mm) After 2 hours 134 133 137 122 131 Bending strength after curing of 6 hours (MPa) 1.5 1.4 1.4 1.5 1.3 Bending strength after curing of 12 hours (MPa) 1.9 1.8 1.7 2 1.8 Bending strength after curing of 24 hours (MPa) 2.5 2.3 2.4 2.5 2.4 Wear amount in rotary corrosion test/mm 6.5 6.6 6.2 6.2 6.3 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 23 Comparative Comparative Comparative Example 136 Example 137 Example 11 Example 12 Example 13 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 11.6 11.5 11.2 11.2 10.8 solution B obtained by SrCO₃ 40 39.5 38.7 38.7 37.4 dissolving Ca α-Al₂O₃ 39.4 39 38.1 38.1 36.8 components in β-SrAl₂O₄ SiO₂ 0 2 12 0 3 including various impurity MgO 0 2 0 12 3 components (mass %) BaO 0 2 0 0 3 TiO₂ 0 2 0 0 3 Fe₂O₃ 9 2 0 0 3 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 50 52 54 56 50 Blending ratio of solid solution B (mass %) 100 100 100 100 100 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 7.8 7.8 7.5 7.6 7.2 of chemical SrO 33.6 33.1 32.3 32.3 31 components of Al₂O₃ 47.6 47.1 45.6 45.7 43.9 binder (mass %) Total amount of SiO₂, 10.8 12 14.5 14.3 17.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 167 173 169 163 170 value (mm) After 2 hours 123 131 140 143 129 Bending strength after curing of 6 hours (MPa) 1.4 1.4 0.7 0.6 0.8 Bending strength after curing of 12 hours (MPa) 1.8 1.9 1.2 1.1 1.2 Bending strength after curing of 24 hours (MPa) 2.5 2.4 1.7 1.7 1.6 Wear amount in rotary corrosion test/mm 6.9 6.5 7.6 6.7 7.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 24 Comparative Example 14 Example 138 Example 139 Example 140 Example 141 Raw materials of solid CaCO₃ — 1.8 1.8 1.8 1.8 solution A obtained by SrCO₃ — 51.7 51.7 51.7 51.1 dissolving Ca α-Al₂O₃ — 37.5 37.5 37.5 37.1 components in α-SrAl₂O₄ SiO₂ — 9 0 0 2 including various impurity MgO — 0 9 0 2 components (mass %) BaO — 0 0 9 2 TiO₂ — 0 0 0 2 Fe₂O₃ — 0 0 0 2 X value of Ca_(x)Sr_(1−x)Al₂O₄ — 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) — 55 63 60 57 Blending ratio of solid solution A (mass %) 0 40 40 40 40 Raw materials of solid CaCO₃ 10.2 — — — — solution B obtained by SrCO₃ 35.1 — — — — dissolving Ca α-Al₂O₃ 34.7 — — — — components in β-SrAl₂O₄ SiO₂ 4 — — — — including various impurity MgO 4 — — — — components (mass %) BaO 4 — — — — TiO₂ 4 — — — — Fe₂O₃ 4 — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 — — — — Crystallite diameter of solid solution B (nm) 48 — — — — Blending ratio of solid solution B (mass %) 100 0 0 0 0 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 60 60 60 60 Measured value CaO 6.8 0.5 0.6 0.5 0.5 of chemical SrO 28.8 17 17.2 17.2 16.8 components of Al₂O₃ 41 78.1 78 78 77.7 binder (mass %) Total amount of SiO₂, 23.3 4.3 4.2 4.3 4.9 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 161 172 174 175 177 value (mm) After 2 hours 120 132 137 133 135 Bending strength after curing of 6 hours (MPa) 0.7 1.2 1.3 1.3 1.3 Bending strength after curing of 12 hours (MPa) 1 1.5 1.6 1.7 1.6 Bending strength after curing of 24 hours (MPa) 1.4 2 2.1 1.9 2.1 Wear amount in rotary corrosion test/mm 8.1 5.8 5.7 5.7 5.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 25 Example 142 Example 143 Example 144 Example 145 Example 146 Raw materials of solid CaCO₃ 1.7 1.6 — — — solution A obtained by SrCO₃ 48.3 45.4 — — — dissolving Ca α-Al₂O₃ 35 33 — — — components in α-SrAl₂O₄ SiO₂ 3 4 — — — including various impurity MgO 3 4 — — — components (mass %) BaO 3 4 — — — TiO₂ 3 4 — — — Fe₂O₃ 3 4 — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 — — — Crystallite diameter of solid solution A (nm) 60 52 — — — Blending ratio of solid solution A (mass %) 40 40 0 0 0 Raw materials of solid CaCO₃ — — 11.6 11.6 11.6 solution B obtained by SrCO₃ — — 40 40 40 dissolving Ca α-Al₂O₃ — — 39.4 39.4 39.4 components in β-SrAl₂O₄ SiO₂ — — 9 0 0 including various impurity MgO — — 0 9 0 components (mass %) BaO — — 0 0 9 TiO₂ — — 0 0 0 Fe₂O₃ — — 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) — — 52 58 58 Blending ratio of solid solution B (mass %) 0 0 40 40 40 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Measured value CaO 0.4 0.4 3 3.1 3.1 of chemical SrO 15.8 14.6 13.3 13.4 13.5 components of Al₂O₃ 76.5 75.4 79.2 78.9 79 binder (mass %) Total amount of SiO₂, 7.1 9.5 4.4 4.5 4.3 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 173 171 170 169 172 value (mm) After 2 hours 130 133 132 130 131 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.2 1.3 Bending strength after curing of 12 hours (MPa) 1.8 1.7 1.6 1.5 1.6 Bending strength after curing of 24 hours (MPa) 2 2.1 2 2.1 2.1 Wear amount in rotary corrosion test/mm 6.1 6.7 5.7 5.7 5.9 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 26 Example 147 Example 148 Example 149 Example 150 Example 151 Raw materials of solid CaCO₃ — — — 1.9 1.9 solution A obtained by SrCO₃ — — — 54.5 54.5 dissolving Ca α-Al₂O₃ — — — 39.6 39.6 components in α-SrAl₂O₄ SiO₂ — — — 4 0 including various impurity MgO — — — 0 4 components (mass %) BaO — — — 0 0 TiO₂ — — — 0 0 Fe₂O₃ — — — 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — 0.05 0.05 Crystallite diameter of solid solution A (nm) — — — 56 61 Blending ratio of solid solution A (mass %) 0 0 0 50 50 Raw materials of solid CaCO₃ 11.5 10.8 10.2 — — solution B obtained by SrCO₃ 39.5 37.4 35.1 — — dissolving Ca α-Al₂O₃ 39 36.8 34.7 — — components in β-SrAl₂O₄ SiO₂ 2 3 4 — — including various impurity MgO 2 3 4 — — components (mass %) BaO 2 3 4 — — TiO₂ 2 3 4 — — Fe₂O₃ 2 3 4 — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 — — Crystallite diameter of solid solution B (nm) 52 50 48 — — Blending ratio of solid solution B (mass %) 40 40 40 0 0 Raw materials of solid CaCO₃ — — — 44.7 44.7 solution C obtained by SrCO₃ — — — 3.4 3.4 dissolving Sr α-Al₂O₃ — — — 47.9 47.9 components in CaAl₂O₄ SiO₂ — — — 4 0 including various impurity MgO — — — 0 4 components (mass %) BaO — — — 0 0 TiO₂ — — — 0 0 Fe₂O₃ — — — 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — 0.95 0.95 Crystallite diameter of solid solution C (nm) — — — 49 52 Blending ratio of solid solution C (mass %) 0 0 0 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 0 0 Measured value CaO 3.1 2.9 2.7 16.2 16.1 of chemical SrO 13.1 12.4 11.5 24.9 24.9 components of Al₂O₃ 78.8 77.5 76.4 54.2 54.1 binder (mass %) Total amount of SiO₂, 4.9 7.3 9.4 4.7 4.9 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 174 171 174 183 181 value (mm) After 2 hours 131 127 127 137 138 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.4 1.4 Bending strength after curing of 12 hours (MPa) 1.6 1.6 1.5 1.7 1.7 Bending strength after curing of 24 hours (MPa) 2 2.1 1.9 2.6 2.5 Wear amount in rotary corrosion test/mm 6.1 6.4 6.9 6.7 6.6 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 27 Example 152 Example 153 Example 154 Example 155 Example 156 Raw materials of solid CaCO₃ 1.9 1.9 1.9 1.9 1.9 solution A obtained by SrCO₃ 54.5 54.5 54.5 53.9 51.7 dissolving Ca α-Al₂O₃ 39.6 39.6 39.6 39.2 37.5 components in α-SrAl₂O₄ SiO₂ 0 0 0 1 9 including various impurity MgO 0 0 0 1 0 components (mass %) BaO 4 0 0 1 0 TiO₂ 0 4 0 1 0 Fe₂O₃ 0 0 4 1 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 56 61 56 58 55 Blending ratio of solid solution A (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ — — — — — solution B obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in β-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution B (nm) — — — — — Blending ratio of solid solution B (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 44.7 44.7 44.7 44.2 44.3 solution C obtained by SrCO₃ 3.4 3.4 3.4 3.4 3.3 dissolving Sr α-Al₂O₃ 47.9 47.9 47.9 47.9 45.4 components in CaAl₂O₄ SiO₂ 0 0 0 1 9 including various impurity MgO 0 0 0 1 0 components (mass %) BaO 4 0 0 1 0 TiO₂ 0 4 0 1 0 Fe₂O₃ 0 0 4 1 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 51 48 46 49 48 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 16.1 16 16.1 15.9 15 of chemical SrO 24.9 24.9 24.7 24.6 23.2 components of Al₂O₃ 54.1 54.3 54.1 53.4 50.7 binder (mass %) Total amount of SiO₂, 4.9 4.8 5 6 11 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 179 184 181 183 180 value (mm) After 2 hours 137 136 135 134 139 Bending strength after curing of 6 hours (MPa) 1.6 1.5 1.4 1.4 1.4 Bending strength after curing of 12 hours (MPa) 2 1.9 1.9 1.8 1.8 Bending strength after curing of 24 hours (MPa) 2.4 2.3 2.5 2.4 2.3 Wear amount in rotary corrosion test/mm 6.9 6.6 6.7 6.9 7.1 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 28 Example 157 Example 158 Example 159 Example 160 Example 161 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.8 1.8 solution A obtained by SrCO₃ 51.7 51.7 51.7 51.7 51.1 dissolving Ca α-Al₂O₃ 37.5 37.5 37.5 37.5 37.1 components in α-SrAl₂O₄ SiO₂ 0 0 0 0 2 including various impurity MgO 9 0 0 0 2 components (mass %) BaO 0 9 0 0 2 TiO₂ 0 0 9 0 2 Fe₂O₃ 0 0 0 9 2 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 63 60 55 54 57 Blending ratio of solid solution A (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ — — — — — solution B obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in β-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution B (nm) — — — — — Blending ratio of solid solution B (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 42.3 42.3 42.3 42.3 42.3 solution C obtained by SrCO₃ 3.3 3.3 3.3 3.3 3.2 dissolving Sr α-Al₂O₃ 45.4 45.4 45.4 45.4 44.9 components in CaAl₂O₄ SiO₂ 0 0 0 0 2 including various impurity MgO 9 0 0 0 2 components (mass %) BaO 0 9 0 0 2 TiO₂ 0 0 9 0 2 Fe₂O₃ 0 0 0 9 2 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 53 54 48 44 46 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 15 14.9 15.2 15 14.9 of chemical SrO 23.3 23.4 23.3 23.3 23 components of Al₂O₃ 50.6 50.6 50.7 50.6 50.1 binder (mass %) Total amount of SiO₂, 10.9 11 10.7 10.9 11.9 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 184 181 178 182 180 value (mm) After 2 hours 138 125 140 130 134 Bending strength after curing of 6 hours (MPa) 1.4 1.5 1.3 1.4 1.4 Bending strength after curing of 12 hours (MPa) 1.7 1.9 1.7 1.7 1.8 Bending strength after curing of 24 hours (MPa) 2.4 2.5 2.4 2.4 2.5 Wear amount in rotary corrosion test/mm 6.8 6.8 6.9 7.1 6.9 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 29 Comparative Comparative Comparative Comparative Example 15 Example 16 Example 17 Example 18 Example 162 Raw materials of solid CaCO₃ 1.8 1.8 1.7 1.6 — solution A obtained by SrCO₃ 49.9 49.9 48.3 45.4 — dissolving Ca α-Al₂O₃ 36.3 36.3 35 33 — components in α-SrAl₂O₄ SiO₂ 12 0 3 4 — including various impurity MgO 0 12 3 4 — components (mass %) BaO 0 0 3 4 — TiO₂ 0 0 3 4 — Fe₂O₃ 0 0 3 4 — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 — Crystallite diameter of solid solution A (nm) 54 62 60 52 — Blending ratio of solid solution A (mass %) 50 50 50 50 0 Raw materials of solid CaCO₃ — — — — 12.3 solution B obtained by SrCO₃ — — — — 42.2 dissolving Ca α-Al₂O₃ — — — — 41.5 components in β-SrAl₂O₄ SiO₂ — — — — 4 including various impurity MgO — — — — 0 components (mass %) BaO — — — — 0 TiO₂ — — — — 0 Fe₂O₃ — — — — 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — 0.3 Crystallite diameter of solid solution B (nm) — — — — 54 Blending ratio of solid solution B (mass %) 0 0 0 0 50 Raw materials of solid CaCO₃ 40.9 40.9 39.6 37.3 44.7 solution C obtained by SrCO₃ 3.2 3.2 3.1 2.9 3.4 dissolving Sr α-Al₂O₃ 43.9 43.9 42.3 39.8 47.9 components in CaAl₂O₄ SiO₂ 12 0 3 4 4 including various impurity MgO 0 12 3 4 0 components (mass %) BaO 0 0 3 4 0 TiO₂ 0 0 3 4 0 Fe₂O₃ 0 0 3 4 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 46 49 47 45 49 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 14.5 14.3 14 12.9 19.8 of chemical SrO 22.4 22.5 21.6 19.9 19.7 components of Al₂O₃ 48.6 48.6 46.5 43.3 55.5 binder (mass %) Total amount of SiO₂, 14.5 14.5 17.8 23.8 5 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 176 169 178 166 174 value (mm) After 2 hours 126 121 129 123 130 Bending strength after curing of 6 hours (MPa) 0.6 0.5 0.7 0.6 1.3 Bending strength after curing of 12 hours (MPa) 0.9 0.7 1 1 1.7 Bending strength after curing of 24 hours (MPa) 1.1 1 1.3 1.3 2.5 Wear amount in rotary corrosion test/mm 7.5 7 7.6 8 6.2 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 30 Example 163 Example 164 Example 165 Example 166 Example 167 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 12.3 12.3 12.3 12.3 12.1 solution B obtained by SrCO₃ 42.2 42.2 42.2 42.2 41.7 dissolving Ca α-Al₂O₃ 41.5 41.5 41.5 41.5 41.2 components in β-SrAl₂O₄ SiO₂ 0 0 0 0 1 including various impurity MgO 4 0 0 0 1 components (mass %) BaO 0 4 0 0 1 TiO₂ 0 0 4 0 1 Fe₂O₃ 0 0 0 4 1 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 56 56 53 53 54 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 44.7 44.7 44.7 44.7 44.2 solution C obtained by SrCO₃ 3.4 3.4 3.4 3.4 3.4 dissolving Sr α-Al₂O₃ 47.9 47.9 47.9 47.9 47.4 components in CaAl₂O₄ SiO₂ 0 0 0 0 1 including various impurity MgO 4 0 0 0 1 components (mass %) BaO 0 4 0 0 1 TiO₂ 0 0 4 0 1 Fe₂O₃ 0 0 0 4 1 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 52 51 48 46 49 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 19.9 19.8 19.6 19.6 19.5 of chemical SrO 19.5 19.7 19.8 19.5 19.5 components of Al₂O₃ 55.6 55.7 55.5 55.8 54.8 binder (mass %) Total amount of SiO₂, 4.9 4.8 5 5.1 6.1 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 176 171 175 174 176 value (mm) After 2 hours 131 129 134 131 131 Bending strength after curing of 6 hours (MPa) 1.3 1.4 1.3 1.4 1.4 Bending strength after curing of 12 hours (MPa) 1.7 1.8 1.7 1.8 1.9 Bending strength after curing of 24 hours (MPa) 2.6 2.5 2.5 2.5 2.6 Wear amount in rotary corrosion test/mm 6.1 6.2 6.2 6.7 6.3 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 31 Example 168 Example 169 Example 170 Example 171 Example 172 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 11.6 11.6 11.6 11.6 11.6 solution B obtained by SrCO₃ 40 40 40 40 40 dissolving Ca α-Al₂O₃ 39.4 39.4 39.4 39.4 39.4 components in β-SrAl₂O₄ SiO₂ 9 0 0 0 0 including various impurity MgO 0 9 0 0 0 components (mass %) BaO 0 0 9 0 0 TiO₂ 0 0 0 9 0 Fe₂O₃ 0 0 0 0 9 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 52 58 58 52 50 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 42.3 42.3 42.3 42.3 42.3 solution C obtained by SrCO₃ 3.3 3.3 3.3 3.3 3.3 dissolving Sr α-Al₂O₃ 45.4 45.4 45.4 45.4 45.4 components in CaAl₂O₄ SiO₂ 9 0 0 0 0 including various impurity MgO 0 9 0 0 0 components (mass %) BaO 0 0 9 0 0 TiO₂ 0 0 0 9 0 Fe₂O₃ 0 0 0 0 9 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 48 53 54 48 44 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 18.5 18.5 18.4 18.5 18.4 of chemical SrO 18.2 18.3 18.3 18.4 18.4 components of Al₂O₃ 52.1 52.1 52.3 52 51.9 binder (mass %) Total amount of SiO₂, 11.1 11 10.9 11 11.2 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 173 177 170 169 173 value (mm) After 2 hours 133 134 127 139 133 Bending strength after curing of 6 hours (MPa) 1.3 1.3 1.4 1.2 1.2 Bending strength after curing of 12 hours (MPa) 1.8 1.7 1.9 1.7 1.7 Bending strength after curing of 24 hours (MPa) 2.6 2.5 2.5 2.4 2.4 Wear amount in rotary corrosion test/mm 6.5 6.3 6.4 6.5 7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 32 Comparative Comparative Comparative Comparative Example 173 Example 19 Example 20 Example 21 Example 22 Raw materials of solid CaCO₃ — — — — — solution A obtained by SrCO₃ — — — — — dissolving Ca α-Al₂O₃ — — — — — components in α-SrAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution A (nm) — — — — — Blending ratio of solid solution A (mass %) 0 0 0 0 0 Raw materials of solid CaCO₃ 11.5 11.2 11.2 10.8 10.2 solution B obtained by SrCO₃ 39.5 38.7 38.7 37.4 35.1 dissolving Ca α-Al₂O₃ 39 38.1 38.1 36.8 34.7 components in β-SrAl₂O₄ SiO₂ 2 12 0 3 4 including various impurity MgO 2 0 12 3 4 components (mass %) BaO 2 0 0 3 4 TiO₂ 2 0 0 3 4 Fe₂O₃ 2 0 0 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 52 54 56 50 48 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 41.9 40.9 40.9 39.6 37.3 solution C obtained by SrCO₃ 3.2 3.2 3.2 3.1 2.9 dissolving Sr α-Al₂O₃ 44.9 43.9 43.9 42.3 39.8 components in CaAl₂O₄ SiO₂ 2 12 0 3 4 including various impurity MgO 2 0 12 3 4 components (mass %) BaO 2 0 0 3 4 TiO₂ 2 0 0 3 4 Fe₂O₃ 2 0 0 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 46 46 49 47 45 Blending ratio of solid solution C (mass %) 50 50 50 50 50 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 18.3 17.7 17.9 17 15.8 of chemical SrO 18.1 17.6 17.7 17.1 15.8 components of Al₂O₃ 51.4 50 49.7 47.8 44.7 binder (mass %) Total amount of SiO₂, 12 14.6 14.6 18 23.7 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 172 167 162 170 164 value (mm) After 2 hours 131 132 127 126 120 Bending strength after curing of 6 hours (MPa) 1.3 0.6 0.5 0.6 0.6 Bending strength after curing of 12 hours (MPa) 1.8 0.9 0.8 0.9 0.8 Bending strength after curing of 24 hours (MPa) 2.5 1.3 1.3 1.4 1.2 Wear amount in rotary corrosion test/mm 6.8 7.5 7.1 7.7 8.1 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 33 Example 174 Example 175 Example 176 Example 177 Example 178 Raw materials of solid CaCO₃ 1.9 1.9 1.9 1.9 1.9 solution A obtained by SrCO₃ 54.5 54.5 54.5 54.5 54.5 dissolving Ca α-Al₂O₃ 39.6 39.6 39.6 39.6 39.6 components in α-SrAl₂O₄ SiO₂ 4 0 0 0 0 including various impurity MgO 0 4 0 0 0 components (mass %) BaO 0 0 4 0 0 TiO₂ 0 0 0 4 0 Fe₂O₃ 0 0 0 0 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 56 61 56 61 56 Blending ratio of solid solution A (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 12.3 12.3 12.3 12.3 12.3 solution B obtained by SrCO₃ 42.2 42.2 42.2 42.2 42.2 dissolving Ca α-Al₂O₃ 41.5 41.5 41.5 41.5 41.5 components in β-SrAl₂O₄ SiO₂ 4 0 0 0 0 including various impurity MgO 0 4 0 0 0 components (mass %) BaO 0 0 4 0 0 TiO₂ 0 0 0 4 0 Fe₂O₃ 0 0 0 0 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 54 56 56 53 53 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 4.8 4.9 4.8 4.8 4.7 of chemical SrO 41 41 40.9 40.9 41.1 components of Al₂O₃ 49.4 49.4 49.4 49.6 49.4 binder (mass %) Total amount of SiO₂, 4.7 4.6 4.8 4.6 4.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 173 175 170 173 170 value (mm) After 2 hours 127 130 125 131 134 Bending strength after curing of 6 hours (MPa) 1.4 1.5 1.4 1.3 1.5 Bending strength after curing of 12 hours (MPa) 1.9 1.9 1.9 1.8 1.8 Bending strength after curing of 24 hours (MPa) 2.3 2.4 2.3 2.4 2.3 Wear amount in rotary corrosion test/mm 6.6 6.5 6.6 6.5 6.8 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 34 Example 179 Example 180 Example 181 Example 182 Example 183 Raw materials of solid CaCO₃ 1.9 1.8 1.8 1.8 59 1.8 solution A obtained by SrCO₃ 53.9 51.7 51.7 51.7 51.7 dissolving Ca α-Al₂O₃ 39.2 37.5 37.5 37.5 37.5 components in α-SrAl₂O₄ SiO₂ 1 9 0 0 0 including various impurity MgO 1 0 9 0 0 components (mass %) BaO 1 0 0 9 0 TiO₂ 1 0 0 0 9 Fe₂O₃ 1 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 58 55 63 60 55 Blending ratio of solid solution A (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 12.1 11.6 11.6 11.6 11.6 solution B obtained by SrCO₃ 41.7 40 40 40 40 dissolving Ca α-Al₂O₃ 41.2 39.4 39.4 39.4 39.4 components in β-SrAl₂O₄ SiO₂ 1 9 0 0 0 including various impurity MgO 1 0 9 0 0 components (mass %) BaO 1 0 0 9 0 TiO₂ 1 0 0 0 9 Fe₂O₃ 1 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 54 52 58 58 52 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of as α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value Cao 4.7 4.4 4.5 4.5 4.5 of chemical SrO 40.3 38.4 38.4 38.4 38.4 components of Al₂O₃ 49 46.4 46.2 46.3 46.3 binder (mass %) Total amount of SiO₂, 5.9 10.7 10.9 10.8 10.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 175 170 173 169 172 value (mm) After 2 hours 135 137 135 126 139 Bending strength after curing of 6 hours (MPa) 1.5 1.4 1.4 1.5 1.3 Bending strength after curing of 12 hours (MPa) 1.9 1.8 1.9 1.9 1.8 Bending strength after curing of 24 hours (MPa) 2.5 2.3 2.4 2.5 2.3 Wear amount in rotary corrosion test/mm 6.7 6.9 6.7 6.7 6.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 35 Comparative Comparative Comparative Example 184 Example 185 Example 23 Example 24 Example 25 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.8 1.7 solution A obtained by SrCO₃ 51.7 51.1 49.9 49.9 48.3 dissolving Ca α-Al₂O₃ 37.5 37.1 36.3 36.3 35 components in α-SrAl₂O₄ SiO₂ 0 2 12 0 3 including various impurity MgO 0 2 0 12 3 components (mass %) BaO 0 2 0 0 3 TiO₂ 0 2 0 0 3 Fe₂O₃ 9 2 0 0 3 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 54 57 54 62 60 Blending ratio of solid solution A (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ 11.6 11.5 11.2 11.2 10.8 solution B obtained by SrCO₃ 40 39.5 38.7 38.7 37.4 dissolving Ca α-Al₂O₃ 39.4 39 38.1 38.1 36.8 components in β-SrAl₂O₄ SiO₂ 0 2 12 0 3 including various impurity MgO 0 2 0 12 3 components (mass %) BaO 0 2 0 0 3 TiO₂ 0 2 0 0 3 Fe₂O₃ 9 2 0 0 3 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 50 52 54 56 50 Blending ratio of solid solution B (mass %) 50 50 50 50 50 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 4.3 4.4 4.3 4.3 4.1 of chemical SrO 38.5 37.9 36.9 36.8 35.3 components of Al₂O₃ 46.1 45.7 44.3 44.6 42.6 binder (mass %) Total amount of SiO₂, 11 11.9 14.4 14.2 17.9 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 167 172 167 164 172 value (mm) After 2 hours 134 136 130 135 132 Bending strength after curing of 6 hours (MPa) 1.3 1.4 0.6 0.5 0.7 Bending strength after curing of 12 hours (MPa) 1.8 1.9 0.9 0.8 1 Bending strength after curing of 24 hours (MPa) 2.4 2.3 1.3 1.3 1.4 Wear amount in rotary corrosion test/mm 7.1 6.9 7.2 6.9 7.3 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 36 Comparative Example 26 Example 186 Example 187 Example 188 Example 189 Raw materials of solid CaCO₃ 1.6 1.9 1.9 1.9 1.9 solution A obtained by SrCO₃ 45.4 54.5 54.5 54.5 54.5 dissolving Ca α-Al₂O₃ 33 39.6 39.6 39.6 39.6 components in α-SrAl₂O₄ SiO₂ 4 4 0 0 0 including various impurity MgO 4 0 4 0 0 components (mass %) BaO 4 0 0 4 0 TiO₂ 4 0 0 0 4 Fe₂O₃ 4 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 52 56 61 56 61 Blending ratio of solid solution A (mass %) 50 35 35 35 35 Raw materials of solid CaCO₃ 10.2 12.3 12.3 12.3 12.3 solution B obtained by SrCO₃ 35.1 42.2 42.2 42.2 42.2 dissolving Ca α-Al₂O₃ 34.7 41.5 41.5 41.5 41.5 components in β-SrAl₂O₄ SiO₂ 4 4 0 0 0 including various impurity MgO 4 0 4 0 0 components (mass %) BaO 4 0 0 4 0 TiO₂ 4 0 0 0 4 Fe₂O₃ 4 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 48 54 56 56 53 Blending ratio of solid solution B (mass %) 50 35 35 35 35 Raw materials of solid CaCO₃ — 44.7 44.7 44.7 44.7 solution C obtained by SrCO₃ — 3.4 3.4 3.4 3.4 dissolving Sr α-Al₂O₃ — 47.9 47.9 47.9 47.9 components in CaAl₂O₄ SiO₂ — 4 0 0 0 including various impurity MgO — 0 4 0 0 components (mass %) BaO — 0 0 4 0 TiO₂ — 0 0 0 4 Fe₂O₃ — 0 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) — 49 52 51 48 Blending ratio of solid solution C (mass %) 0 30 30 30 30 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 3.8 12.6 12.5 12.8 12.7 of chemical SrO 32.7 29.7 29.8 29.6 29.8 components of Al₂O₃ 39.9 52.6 52.7 52.7 52.6 binder (mass %) Total amount of SiO₂, 23.5 5 4.9 4.8 4.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 165 166 169 163 170 value (mm) After 2 hours 122 134 136 128 135 Bending strength after curing of 6 hours (MPa) 0.5 1.4 1.4 1.5 1.3 Bending strength after curing of 12 hours (MPa) 0.9 1.7 1.8 1.8 1.6 Bending strength after curing of 24 hours (MPa) 1.3 2.6 2.6 2.5 2.6 Wear amount in rotary corrosion test/mm 7.5 6.7 6.8 6.7 6.6 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 37 Example 190 Example 191 Example 192 Example 193 Example 194 Raw materials of solid CaCO₃ 1.9 1.9 1.8 1.8 1.8 solution A obtained by SrCO₃ 54.5 53.9 51.7 51.7 51.7 dissolving Ca α-Al₂O₃ 39.6 39.2 37.5 37.5 37.5 components in α-SrAl₂O₄ SiO₂ 0 1 9 0 0 including various impurity MgO 0 1 0 9 0 components (mass %) BaO 0 1 0 0 9 TiO₂ 0 1 0 0 0 Fe₂O₃ 4 1 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 56 58 55 63 60 Blending ratio of solid solution A (mass %) 35 35 35 35 35 Raw materials of solid CaCO₃ 12.3 12.1 11.6 11.6 11.6 solution B obtained by SrCO₃ 42.2 41.7 40 40 40 dissolving Ca α-Al₂O₃ 41.5 41.2 39.4 39.4 39.4 components in β-SrAl₂O₄ SiO₂ 0 1 9 0 0 including various impurity MgO 0 1 0 9 0 components (mass %) BaO 0 1 0 0 9 TiO₂ 0 1 0 0 0 Fe₂O₃ 4 1 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 53 54 52 58 58 Blending ratio of solid solution B (mass %) 35 35 35 35 35 Raw materials of solid CaCO₃ 44.7 44.2 42.3 42.3 42.3 solution C obtained by SrCO₃ 3.4 3.4 3.3 3.3 3.3 dissolving Sr α-Al₂O₃ 47.9 47.4 45.4 45.4 45.4 components in CaAl₂O₄ SiO₂ 0 1 9 0 0 including various impurity MgO 0 1 0 9 0 components (mass %) BaO 0 1 0 0 9 TiO₂ 0 1 0 0 0 Fe₂O₃ 4 1 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 46 49 48 53 54 Blending ratio of solid solution C (mass %) 30 30 30 30 30 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 12.6 12.4 11.8 11.8 11.9 of chemical SrO 29.8 29.3 27.9 27.9 27.9 components of Al₂O₃ 52.5 51.9 49.3 49.3 49.3 binder (mass %) Total amount of SiO₂, 5 6.3 10.9 10.9 10.8 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 168 171 170 172 163 value (mm) After 2 hours 134 135 137 136 124 Bending strength after curing of 6 hours (MPa) 1.4 1.4 1.3 1.3 1.5 Bending strength after curing of 12 hours (MPa) 1.7 1.8 1.7 1.6 1.9 Bending strength after curing of 24 hours (MPa) 2.7 2.6 2.5 2.4 2.5 Wear amount in rotary corrosion test/mm 7 6.8 7 6.5 6.8 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 38 Comparative Comparative Example 195 Example 196 Example 197 Example 27 Example 28 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.8 1.8 solution A obtained by SrCO₃ 51.7 51.7 51.1 49.9 49.9 dissolving Ca α-Al₂O₃ 37.5 37.5 37.1 36.3 36.3 components in α-SrAl₂O₄ SiO₂ 0 0 2 12 0 including various impurity MgO 0 0 2 0 12 components (mass %) BaO 0 0 2 0 0 TiO₂ 9 0 2 0 0 Fe₂O₃ 0 9 2 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 55 54 57 54 62 Blending ratio of solid solution A (mass %) 35 35 35 35 35 Raw materials of solid CaCO₃ 11.6 11.6 11.5 11.2 11.2 solution B obtained by SrCO₃ 40 40 39.5 38.7 38.7 dissolving Ca α-Al₂O₃ 39.4 39.4 39 38.1 38.1 components in β-SrAl₂O₄ SiO₂ 0 0 2 12 0 including various impurity MgO 0 0 2 0 12 components (mass %) BaO 0 0 2 0 0 TiO₂ 9 0 2 0 0 Fe₂O₃ 0 9 2 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 52 50 52 54 56 Blending ratio of solid solution B (mass %) 35 35 35 35 35 Raw materials of solid CaCO₃ 42.3 42.3 41.9 40.9 40.9 solution C obtained by SrCO₃ 3.3 3.3 3.2 3.2 3.2 dissolving Sr α-Al₂O₃ 45.4 45.4 44.9 43.9 43.9 components in CaAl₂O₄ SiO₂ 0 0 2 12 0 including various impurity MgO 0 0 2 0 12 components (mass %) BaO 0 0 2 0 0 TiO₂ 9 0 2 0 0 Fe₂O₃ 0 9 2 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 48 44 46 46 49 Blending ratio of solid solution C (mass %) 30 30 30 30 30 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 0 0 0 Measured value CaO 11.8 11.8 11.7 11.4 11.3 of chemical SrO 27.9 27.9 27.5 26.6 26.7 components of Al₂O₃ 49.3 49.3 48.7 47.2 47.4 binder (mass %) Total amount of SiO₂, 10.9 10.9 12 14.7 14.5 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 170 166 168 166 161 value (mm) After 2 hours 140 138 137 141 131 Bending strength after curing of 6 hours (MPa) 1.3 1.3 1.4 0.6 0.5 Bending strength after curing of 12 hours (MPa) 1.6 1.6 1.7 0.9 0.8 Bending strength after curing of 24 hours (MPa) 2.5 2.6 2.4 1.4 1.2 Wear amount in rotary corrosion test/mm 6.7 7.1 7 7.6 7.1 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 39 Comparative Comparative Example 29 Example 30 Example 198 Example 199 Example 200 Raw materials of solid CaCO₃ 1.7 1.6 1.8 1.8 1.8 solution A obtained by SrCO₃ 48.3 45.4 51.7 51.7 51.7 dissolving Ca α-Al₂O₃ 35 33 37.5 37.5 37.5 components in α-SrAl₂O₄ SiO₂ 3 4 9 0 0 including various impurity MgO 3 4 0 9 0 components (mass %) BaO 3 4 0 0 9 TiO₂ 3 4 0 0 0 Fe₂O₃ 3 4 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 60 52 55 63 60 Blending ratio of solid solution A (mass %) 35 35 20 20 20 Raw materials of solid CaCO₃ 10.8 10.2 — — — solution B obtained by SrCO₃ 37.4 35.1 — — — dissolving Ca α-Al₂O₃ 36.8 34.7 — — — components in β-SrAl₂O₄ SiO₂ 3 4 — — — including various impurity MgO 3 4 — — — components (mass %) BaO 3 4 — — — TiO₂ 3 4 — — — Fe₂O₃ 3 4 — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 — — — Crystallite diameter of solid solution B (nm) 50 48 — — — Blending ratio of solid solution B (mass %) 35 35 0 0 0 Raw materials of solid CaCO₃ 39.6 37.3 42.3 42.3 42.3 solution C obtained by SrCO₃ 3.1 2.9 3.3 3.3 3.3 dissolving Sr α-Al₂O₃ 42.3 39.8 45.4 45.4 45.4 components in CaAl₂O₄ SiO₂ 3 4 9 0 0 including various impurity MgO 3 4 0 9 0 components (mass %) BaO 3 4 0 0 9 TiO₂ 3 4 0 0 0 Fe₂O₃ 3 4 0 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 47 45 48 53 54 Blending ratio of solid solution C (mass %) 30 30 20 20 20 Blending ratio of α-Al₂O₃ (mass %)*¹ 0 0 60 60 60 Measured value CaO 10.9 10.2 5.9 6 6 of chemical SrO 25.6 23.7 9.3 9.3 9.3 components of Al₂O₃ 45.2 42.3 80.2 80.2 80.4 binder (mass %) Total amount of SiO₂, 18.2 23.7 4.5 4.4 4.3 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 167 160 172 170 168 value (mm) After 2 hours 130 123 138 140 133 Bending strength after curing of 6 hours (MPa) 0.6 0.5 1.3 1.4 1.2 Bending strength after curing of 12 hours (MPa) 0.9 0.8 1.6 1.7 1.6 Bending strength after curing of 24 hours (MPa) 1.3 1.1 2.2 2 2.1 Wear amount in rotary corrosion test/mm 7.6 8 5.8 5.7 5.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 40 Example 201 Example 202 Example 203 Example 204 Example 205 Raw materials of solid CaCO₃ 1.8 1.7 1.6 — — solution A obtained by SrCO₃ 51.1 48.3 45.4 — — dissolving Ca α-Al₂O₃ 37.1 35 33 — — components in α-SrAl₂O₄ SiO₂ 2 3 4 — — including various impurity MgO 2 3 4 — — components (mass %) BaO 2 3 4 — — TiO₂ 2 3 4 — — Fe₂O₃ 2 3 4 — — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 — — Crystallite diameter of solid solution A (nm) 57 60 52 — — Blending ratio of solid solution A (mass %) 20 20 20 0 0 Raw materials of solid CaCO₃ — — — 11.6 11.6 solution B obtained by SrCO₃ — — — 40 40 dissolving Ca α-Al₂O₃ — — — 39.4 39.4 components in β-SrAl₂O₄ SiO₂ — — — 9 0 including various impurity MgO — — — 0 9 components (mass %) BaO — — — 0 0 TiO₂ — — — 0 0 Fe₂O₃ — — — 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — 0.3 0.3 Crystallite diameter of solid solution B (nm) — — — 52 58 Blending ratio of solid solution B (mass %) 0 0 0 20 20 Raw materials of solid CaCO₃ 41.9 39.6 37.3 42.3 42.3 solution C obtained by SrCO₃ 3.2 3.1 2.9 3.3 3.3 dissolving Sr α-Al₂O₃ 44.9 42.3 39.8 45.4 45.4 components in CaAl₂O₄ SiO₂ 2 3 4 9 0 including various impurity MgO 2 3 4 0 9 components (mass %) BaO 2 3 4 0 0 TiO₂ 2 3 4 0 0 Fe₂O₃ 2 3 4 0 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 46 47 45 48 53 Blending ratio of solid solution C (mass %) 20 20 20 20 20 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Measured value CaO 5.9 5.6 5.4 7.4 7.4 of chemical SrO 9.1 8.4 7.8 7.3 7.5 components of Al₂O₃ 80.1 78.8 77.1 80.8 80.7 binder (mass %) Total amount of SiO₂, 4.8 7.1 9.6 4.4 4.3 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 173 167 166 168 170 value (mm) After 2 hours 140 134 130 135 139 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.1 1.1 1.2 Bending strength after curing of 12 hours (MPa) 1.7 1.6 1.5 1.6 1.8 Bending strength after curing of 24 hours (MPa) 2 2 2.1 2.2 2 Wear amount in rotary corrosion test/mm 5.9 6.2 6.6 5.9 5.7 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 41 Example 206 Example 207 Example 208 Example 209 Example 210 Raw materials of solid CaCO₃ — — — — 1.8 solution A obtained by SrCO₃ — — — — 51.7 dissolving Ca α-Al₂O₃ — — — — 37.5 components in α-SrAl₂O₄ SiO₂ — — — — 9 including various impurity MgO — — — — 0 components (mass %) BaO — — — — 0 TiO₂ — — — — 0 Fe₂O₃ — — — — 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — 0.05 Crystallite diameter of solid solution A (nm) — — — — 55 Blending ratio of solid solution A (mass %) 0 0 0 0 20 Raw materials of solid CaCO₃ 11.6 11.5 10.8 10.2 11.6 solution B obtained by SrCO₃ 40 39.5 37.4 35.1 40 dissolving Ca α-Al₂O₃ 39.4 39 36.8 34.7 39.4 components in β-SrAl₂O₄ SiO₂ 0 2 3 4 9 including various impurity MgO 0 2 3 4 0 components (mass %) BaO 9 2 3 4 0 TiO₂ 0 2 3 4 0 Fe₂O₃ 0 2 3 4 0 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 58 52 50 48 52 Blending ratio of solid solution B (mass %) 20 20 20 20 20 Raw materials of solid CaCO₃ 42.3 41.9 39.6 37.3 — solution C obtained by SrCO₃ 3.3 3.2 3.1 2.9 — dissolving Sr α-Al₂O₃ 45.4 44.9 42.3 39.8 — components in CaAl₂O₄ SiO₂ 0 2 3 4 — including various impurity MgO 0 2 3 4 — components (mass %) BaO 9 2 3 4 — TiO₂ 0 2 3 4 — Fe₂O₃ 0 2 3 4 — X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 — Crystallite diameter of solid solution C (nm) 54 46 47 45 — Blending ratio of solid solution C (mass %) 20 20 20 20 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Measured value CaO 7.7 7.4 6.9 6.3 1.9 of chemical SrO 7.4 7.2 6.8 6.2 15.2 components of Al₂O₃ 80.4 80.3 79 77.9 78.6 binder (mass %) Total amount of SiO₂, 4.4 5 7.3 9.5 4.2 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 166 171 167 163 177 value (mm) After 2 hours 132 135 130 133 135 Bending strength after curing of 6 hours (MPa) 1.1 1.1 1 1 1.3 Bending strength after curing of 12 hours (MPa) 1.7 1.6 1.5 1.4 1.7 Bending strength after curing of 24 hours (MPa) 2 2.1 2.1 2 2.4 Wear amount in rotary corrosion test/mm 5.8 6 6.4 6.9 5.8 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 42 Example 211 Example 212 Example 213 Example 214 Example 215 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.7 1.6 solution A obtained by SrCO₃ 51.7 51.7 51.1 48.3 45.4 dissolving Ca α-Al₂O₃ 37.5 37.5 37.1 35 33 components in α-SrAl₂O₄ SiO₂ 0 0 2 3 4 including various impurity MgO 9 0 2 3 4 components (mass %) BaO 0 9 2 3 4 TiO₂ 0 0 2 3 4 Fe₂O₃ 0 0 2 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 63 60 57 60 52 Blending ratio of solid solution A (mass %) 20 20 20 20 20 Raw materials of solid CaCO₃ 11.6 11.6 11.5 10.8 10.2 solution B obtained by SrCO₃ 40 40 39.5 37.4 35.1 dissolving Ca α-Al₂O₃ 39.4 39.4 39 36.8 34.7 components in β-SrAl₂O₄ SiO₂ 0 0 2 3 4 including various impurity MgO 9 0 2 3 4 components (mass %) BaO 0 9 2 3 4 TiO₂ 0 0 2 3 4 Fe₂O₃ 0 0 2 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 58 58 52 50 48 Blending ratio of solid solution B (mass %) 20 20 20 20 20 Raw materials of solid CaCO₃ — — — — — solution C obtained by SrCO₃ — — — — — dissolving Sr α-Al₂O₃ — — — — — components in CaAl₂O₄ SiO₂ — — — — — including various impurity MgO — — — — — components (mass %) BaO — — — — — TiO₂ — — — — — Fe₂O₃ — — — — — X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — Crystallite diameter of solid solution C (nm) — — — — — Blending ratio of solid solution C (mass %) 0 0 0 0 0 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Measured value CaO 1.8 1.8 1.8 1.7 1.4 of chemical SrO 15.2 15.3 14.9 14 13 components of Al₂O₃ 78.5 78.3 78.3 76.9 75.9 binder (mass %) Total amount of SiO₂, 4.4 4.5 4.9 7.3 9.6 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 179 173 180 176 173 value (mm) After 2 hours 136 129 139 136 127 Bending strength after curing of 6 hours (MPa) 1.3 1.4 1.3 1.2 1.1 Bending strength after curing of 12 hours (MPa) 1.8 1.8 1.7 1.7 1.6 Bending strength after curing of 24 hours (MPa) 2.3 2.3 2.4 2.3 2.3 Wear amount in rotary corrosion test/mm 5.6 5.7 5.8 6.3 6.8 Note) *¹Components other than solid solution and CaAl₂O₄

TABLE 43 Example 216 Example 217 Example 218 Example 219 Example 220 Example 221 Raw materials of solid CaCO₃ 1.8 1.8 1.8 1.8 1.7 1.6 solution A obtained by SrCO₃ 51.7 51.7 51.7 51.1 48.3 45.4 dissolving Ca α-Al₂O₃ 37.5 37.5 37.5 37.1 35 33 components in α-SrAl₂O₄ SiO₂ 9 0 0 2 3 4 including various impurity MgO 0 9 0 2 3 4 components (mass %) BaO 0 0 9 2 3 4 TiO₂ 0 0 0 2 3 4 Fe₂O₃ 0 0 0 2 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution A (nm) 55 63 60 57 60 52 Blending ratio of solid solution A (mass %) 14 14 14 14 14 14 Raw materials of solid CaCO₃ 11.6 11.6 11.6 11.5 10.8 10.2 solution B obtained by SrCO₃ 40 40 40 39.5 37.4 35.1 dissolving Ca α-Al₂O₃ 39.4 39.4 39.4 39 36.8 34.7 components in β-SrAl₂O₄ SiO₂ 9 0 0 2 3 4 including various impurity MgO 0 9 0 2 3 4 components (mass %) BaO 0 0 9 2 3 4 TiO₂ 0 0 0 2 3 4 Fe₂O₃ 0 0 0 2 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution B (nm) 52 58 58 52 50 48 Blending ratio of solid solution B (mass %) 14 14 14 14 14 14 Raw materials of solid CaCO₃ 42.3 42.3 42.3 41.9 39.6 37.3 solution C obtained by SrCO₃ 3.3 3.3 3.3 3.2 3.1 2.9 dissolving Sr α-Al₂O₃ 45.4 45.4 45.4 44.9 42.3 39.8 components in CaAl₂O₄ SiO₂ 9 0 0 2 3 4 including various impurity MgO 0 9 0 2 3 4 components (mass %) BaO 0 0 9 2 3 4 TiO₂ 0 0 0 2 3 4 Fe₂O₃ 0 0 0 2 3 4 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution C (nm) 48 53 54 46 47 45 Blending ratio of solid solution C (mass %) 12 12 12 12 12 12 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 Measured value CaO 4.7 4.7 4.8 4.7 4.4 4 of chemical SrO 11 11.1 10.9 10.8 10.3 9.3 components of Al₂O₃ 79.7 79.6 79.8 79.4 78.1 77 binder (mass %) Total amount of SiO₂, 4.5 4.5 4.4 5 7.2 9.6 MgO, BaO, TiO₂, and Fe₂O₃ 15 tap-flow After mixing 165 162 162 167 164 165 value (mm) After 2 hours 140 135 130 138 131 128 Bending strength after curing of 6 hours (MPa) 1.2 1.2 1.3 1.2 1.1 1 Bending strength after curing of 12 hours (MPa) 1.5 1.6 1.7 1.6 1.6 1.5 Bending strength after curing of 24 hours (MPa) 2.2 2.1 2 2 1.9 2 Wear amount in rotary corrosion test/mm 6.1 6 6.1 6.2 6.4 6.9 Note) *¹Components other than solid solution and CaAl₂O₄

The evaluation results are as shown in Tables 17 to 43. Comparative Examples 7 to 30 show degradation in the cured flexural strength and an increase in the wear amount in the rotary corrosion test using slag since they include from 14.8 mass % to 23.8 mass % of one kind or two or more kinds of components selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO other than SrO, CaO, and Al₂O₃ in the binders of the present invention. Examples 110 to 221 show a superior strength developing property compared to a case not including the above-described components and superior high temperature slag resistance compared to CaO—Al₂O₃-based binders of the conventional technique, which clarifies that favorable characteristics can be obtained by including preferably 12 mass % or less and more preferably 5 mass % or less of one kind or two or more kinds of components selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO in the binders.

From these test results, it has been clarified that, by using the binder for monolithic refractories according to the present invention including a solid solution including one kind or two or more kinds selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO in which an amount thereof is 12 mass % or less, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained. Therefore, in the binder for monolithic refractories according to the present invention, when low purity raw materials including impurities such as SiO₂, TiO₂, Fe₂O₃, MgO, and BaO are used or when various contaminations of impurities are generated during the manufacturing process, by adjusting an amount thereof to be 12 mass % or less in a binder, superior characteristics can be obtained compared to CaO—Al₂O₃-based binders of the conventional technique.

[10] Examples relating to a monolithic refractory obtained by blending at least either a dispersant or a hardening retardant in the binders according to the present invention

Measurement of the flow value and the flexural strength after curing and rotary corrosion tests using slag were performed using monolithic refractories manufactured with binders including various solid solutions for which raw materials had been controlled to obtain an X value of Ca_(x)Sr_(1-x)Al₂O₄ of 0.05, 0.30, or 0.95 and firing had been performed for 2 hours at the maximum temperature of 1500° C. for manufacture, into which α-Al₂O₃ was blended with a predetermined ratio and one or two kinds of either a dispersant or a hardening retardant were blended, in Examples 222 to 257. In addition, the same tests were performed using monolithic refractories manufactured with binders including a solid solution for which raw materials had been controlled to obtain a composition of CaAl₂O₄ and firing had been performed for 2 hours at the maximum temperature of 1500° C. for manufacture, into which α-Al₂O₃ was blended with a predetermined ratio, in Comparative Examples 31 to 36. Monolithic refractories were manufactured with an amount of water added reduced to 6.2 mass % with respect to 100 mass % of a mixture of the binder and refractory aggregates. Tables 44 to 47 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the solid solutions, CaAl₂O₄, α-Al₂O₃, the dispersant, and the hardening retardant, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. In the tables, the amounts of the dispersant and the hardening retardant blended are represented by the ratio (mass ratio) to the binders.

A commercially available powder polycarboxylic acid-based dispersant was used as the dispersant, and boric acid (primary reagent) was crushed to 200 mesh or lower and used as the hardening retardant.

TABLE 44 Example Example Example Example Example Example 222 223 224 225 226 227 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by dissolving Ca 59 59 59 59 59 59 components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 40 40 40 40 40 40 components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by dissolving Ca 54 54 54 54 54 54 components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 0 0 0 0 0 0 components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by dissolving Sr 50 50 50 50 50 50 components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Sr 0 0 0 0 0 0 components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 Dispersant (part by mass) 0.5 1 — — 0.5 1 Hardening retardant (part by mass) — — 0.3 0.6 0.3 0.3 15 tap-flow value After mixing 166 184 159 152 171 189 (mm) After 2 hours 121 132 129 133 133 141 Bending strength after curing of 6 hours (MPa) 1.6 1.7 1.4 1.2 1.5 1.3 Bending strength after curing of 12 hours (MPa) 1.9 1.9 1.7 1.5 1.6 1.7 Bending strength after curing of 24 hours (MPa) 2.5 2.5 2.5 2.4 2.5 2.4 Wear amount in rotary corrosion test (mm) 5.4 5.3 5.4 5.5 5.3 5.3 Example Example Example Example Example 228 229 230 231 232 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by dissolving Ca 59 59 59 59 59 components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 0 0 0 0 0 components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by dissolving Ca 54 54 54 54 54 components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Ca 40 40 40 40 40 components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by dissolving Sr 50 50 50 50 50 components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by dissolving Sr 0 0 0 0 0 components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Dispersant (part by mass) 0.5 1 — — 0.5 Hardening retardant (part by mass) — — 0.3 0.6 0.3 15 tap-flow value After mixing 163 177 156 151 164 (mm) After 2 hours 128 131 124 130 131 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.3 1.2 1.4 Bending strength after curing of 12 hours (MPa) 1.9 1.8 1.7 1.5 1.7 Bending strength after curing of 24 hours (MPa) 2.6 2.7 2.7 2.6 2.7 Wear amount in rotary corrosion test (mm) 5.5 5.5 5.4 5.6 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 45 Example Example Example Example Example Example 233 234 235 236 237 238 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 20 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained 0 20 20 20 20 20 by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 Dispersant (part by mass) 1 0.5 1 — — 0.5 Hardening retardant (part by mass) 0.3 — — 0.3 0.6 0.3 15 tap-flow value (mm) After mixing 178 164 181 162 158 171 After 2 hours 138 128 133 133 135 132 Bending strength after curing of 6 hours (MPa) 1.3 1.5 1.5 1.3 1.2 1.5 Bending strength after curing of 12 hours (MPa) 1.6 1.9 1.8 1.8 1.7 1.8 Bending strength after curing of 24 hours (MPa) 2.6 2.6 2.6 2.5 2.6 2.5 Wear amount in rotary corrosion test (mm) 5.3 5.5 5.4 5.6 5.5 5.4 Example Example Example Example Example 239 240 241 242 243 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained 20 20 20 20 20 by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Dispersant (part by mass) 1 0.5 1 — — Hardening retardant (part by mass) 0.3 — — 0.3 0.6 15 tap-flow value (mm) After mixing 185 160 169 152 147 After 2 hours 134 124 127 123 126 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.1 1.1 Bending strength after curing of 12 hours (MPa) 1.7 1.5 1.6 1.5 1.5 Bending strength after curing of 24 hours (MPa) 2.4 2.7 2.6 2.6 2.5 Wear amount in rotary corrosion test (mm) 5.5 5.5 5.6 5.7 5.7 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 46 Example Example Example Example Example 244 245 246 247 248 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained 20 20 0 0 0 by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Dispersant (part by mass) 0.5 1 0.5 1 — Hardening retardant (part by mass) 0.3 0.3 — — 0.3 15 tap-flow value (mm) After mixing 162 166 168 179 159 After 2 hours 129 131 127 132 122 Bending strength after curing of 6 hours (MPa) 1.2 1.2 1.6 1.5 1.4 Bending strength after curing of 12 hours (MPa) 1.6 1.6 2 1.9 1.8 Bending strength after curing of 24 hours (MPa) 2.7 2.5 2.7 2.6 2.6 Wear amount in rotary corrosion test (mm) 5.6 5.5 5.4 5.5 5.5 Example Example Example Example Example 249 250 251 252 253 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 15 15 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 03 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 15 15 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained 0 0 0 10 10 by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 Dispersant (part by mass) — 0.5 1 0.5 1 Hardening retardant (part by mass) 0.6 0.3 0.3 — — 15 tap-flow value (mm) After mixing 153 167 177 162 174 After 2 hours 134 128 132 129 135 Bending strength after curing of 6 hours (MPa) 1.3 1.5 1.4 1.2 1.3 Bending strength after curing of 12 hours (MPa) 1.7 1.8 1.7 1.6 1.7 Bending strength after curing of 24 hours (MPa) 2.5 2.5 2.5 2.7 2.6 Wear amount in rotary corrosion test (mm) 5.7 5.3 5.4 5.4 5.5 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 47 Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative Example Example Example Example Example Example Example Example Example Example 254 255 256 257 31 32 33 34 35 36 X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.05 0.05 0.05 0.05             Crystallite diameter of solid solution 59 59 59 59             obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution 15 15 15 15             obtained by dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.3 0.3 0.3 0.3             Crystallite diameter of solid solution 54 54 54 54             obtained by dissolving Ca components β-SrAl₂O₄ (nm) Blending ratio of solid solution 15 15 15 15             obtained by dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.95 0.95 0.95 0.95             Crystallite diameter of solid solution 50 50 50 50             obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution 10 10 10 10             obtained by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) —       40 40 40 40 40 40 Blending ratio of α-Al₂O₃ (mass %) *1 60 60 60 60 60 60 60 60 60 60 Dispersant (part by mass)     0.5 1 0.5 1     0.5 1 Hardening retardant (part by mass) 0.3 0.6 0.3 0.3     0.3 0.6 0.3 0.3 15 tap-flow value (mm) After mixing 151 150 160 177 161 168 153 147 163 173 After 2 hours 130 137 132 134 122 123 121 125 129 131 Bending strength after curing of 6 1.2 1.1 1.2 1.2 0.3 0.3 0.4 0.2 0.3 0.2 hours (MPa) Bending strength after curing of 1.5 1.4 1.6 1.7 0.7 0.6 0.6 0.5 0.7 0.5 12 hours (MPa ) Bending strength after curing of 2.4 2.5 2.6 2.6 1.8 1.8 1.6 1.3 1.6 1.4 24 hours (MPa) Wear amount in rotary corrosion 5.6 5.5 5.5 5.6 7.6 7.5 7.7 7.8 7.5 7.6 test (mm) Note) *1 Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Tables 44 to 47. In Examples 222 to 257, regardless of the reduced amount of water added to monolithic refractories, the flow values suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 222 to 257 can be applied to furnaces with a large volume or the like. Furthermore, Examples 222 to 257 show larger values than Comparative Examples 31 to 36 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 222 to 257 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 222 to 257 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 222 to 257 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, since monolithic refractories were manufactured with a reduced amount of water added, a decrease in the wear amount in the rotary corrosion test using slag could be obtained compared to a case where monolithic refractories were manufactured with the same composition of binder.

From these test results, it has been clarified that, by using the dispersant and the hardening retardant in the binder for monolithic refractories according to the present invention, a monolithic refractory in which a favorable operability is secured even after a long period of time has elapsed after pouring and blending water thereinto, a favorable strength developing property is obtained early, and slag resistance at a high temperature is superior compared to the conventional technique can be obtained.

[11] Examples relating to a monolithic refractory including a mixture of the binder for monolithic refractories according to the present invention and a refractory aggregate including an ultrafine alumina powder with a particle diameter of 1 μm or less

The same tests were performed using monolithic refractories manufactured from aggregates in which amounts of the ultrafine alumina powder with a particle diameter of 1 μm or less in the monolithic refractories were varied in a range of 0 to 80 mass % and the binder according to the present invention in Examples 258 to 293 and Reference Examples 23 to 34. In all tests, a binder including 40 mass % of various solid solutions and their mixture and 60 mass % of α-Al₂O₃ were used, wherein the solid solutions prepared such that raw materials had been controlled to obtain an X value of Ca_(x)Sr_(1-x)Al₂O₄ of 0.05, 0.30, or 0.95 and firing had been performed for 2 hours at the maximum temperature of 1500° C. The amount of fused alumina of from 75 μm to 5 mm was adjusted to cover a changed amount of the ultrafine alumina powder of 1 μm or less so as to manufacture monolithic refractories with the same total mass of alumina refractory aggregates. Further, the blending ratio of the binder, magnesia, silica flower, vinylon fiber and the amount of water added was not varied. Tables 48 to 52 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the various solid solutions and α-Al₂O₃, the amount of sintered alumina of 1 μm or less, the amount of fused alumina of from 75 μm to 5 mm, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples.

TABLE 48 Example Example Example Example Example Example 258 259 260 261 262 263 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 40 40 40 40 40 40 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 Amount of sintered alumina of 1 μm or less*² (mass %) 2 5 10 30 50 70 Amount of fused alumina of 83.56 80.56 75.56 55.56 35.56 15.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 184 179 176 172 171 162 After 2 hours 131 135 135 133 132 122 Bending strength after curing of 6 hours (MPa) 0.9 1 1 1.1 1.1 1.3 Bending strength after curing of 12 hours (MPa) 1.2 1.3 1.3 1.4 1.4 1.6 Bending strength after curing of 24 hours (MPa) 1.9 1.9 2 1.9 2 2 Wear amount in rotary corrosion test (mm) 6 5.9 5.8 5.8 5.7 5.7 Reference Reference Example Example Example 23 Example 24 264 265 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 40 40 0 0 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 40 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 Amount of sintered alumina of 1 μm or less*² (mass %) 0 80 2 5 Amount of fused alumina of 85.56 5.56 83.56 80.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 181 133 180 177 After 2 hours 136 103 133 135 Bending strength after curing of 6 hours (MPa) 0.5 1.3 0.8 0.9 Bending strength after curing of 12 hours (MPa) 0.8 1.6 1.1 1.2 Bending strength after curing of 24 hours (MPa) 1.2 1.9 2 2 Wear amount in rotary corrosion test (mm) 6 6.3 5.9 5.9 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄ *²Mixing ratio with respect to monolithic refractory (total amount of binder and refractory aggregates)

TABLE 49 Refer- Refer- Ex- Ex- Ex- Ex- ence ence Ex- Ex- Ex- Ex- ample ample ample ample Example Example ample ample ample ample 266 267 268 269 25 26 270 271 272 273 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 0 0 0 0 0 0 20 20 20 20 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 20 20 20 20 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of sintered alumina of 1 μm or less*² 10 30 50 70 0 80 2 5 10 30 (mass %) Amount of fused alumina of 75.56 55.56 35.56 15.56 85.56 5.56 83.56 80.56 75.56 55.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 173 174 167 160 183 141 180 177 175 172 After 2 hours 135 131 128 124 138 105 130 135 132 135 Bending strength after curing of 6 hours (MPa) 0.9 0.9 1.1 1.2 0.4 1.3 0.9 1 1 1.1 Bending strength after curing of 12 hours (MPa) 1.3 1.4 1.5 1.6 0.8 1.7 1.2 1.3 1.3 1.3 Bending strength after curing of 24 hours (MPa) 2.1 2.2 2.2 2.2 1.8 2.3 1.8 1.9 2 2.1 Wear amount in rotary corrosion test (mm) 5.9 5.7 5.7 5.8 6.2 6.4 6.1 5.9 5.9 5.8 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄ *²Mixing ratio with respect to monolithic refractory (total amount of binder and refractory aggregates)

TABLE 50 Refer- Refer- Ex- Ex- ence ence Ex- Ex- Ex- Ex- Ex- Ex- ample ample Example Example ample ample ample ample ample ample 274 275 27 28 276 277 278 279 280 281 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 20 20 20 20 0 0 0 0 0 0 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 20 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of sintered alumina of 1 μm or less*² 50 70 0 80 2 5 10 30 50 70 (mass %) Amount of fused alumina of 35.56 15.56 85.56 5.56 83.56 80.56 75.56 55.56 35.56 15.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 169 160 183 136 178 177 172 170 167 161 After 2 hours 136 129 140 102 146 142 139 139 138 134 Bending strength after curing of 6 hours (MPa) 1.1 1.2 0.5 1.2 0.8 0.8 0.9 1 1 1 Bending strength after curing of 12 hours (MPa) 1.4 1.4 0.7 1.5 1 1.1 1.2 1.2 1.3 1.4 Bending strength after curing of 24 hours (MPa) 2.1 2 1.3 2 2 2.2 2.2 2.1 2.2 2.2 Wear amount in rotary corrosion test (mm) 5.8 5.7 6.2 6.1 6.3 6.2 6 5.9 5.9 5.8 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄ *²Mixing ratio with respect to monolithic refractory (total amount of binder and refractory aggregates)

TABLE 51 Reference Reference Ex- Ex- Ex- Ex- Ex- Ex- Reference Reference Example Example ample ample ample ample ample ample Example Example 29 30 282 283 284 285 286 287 31 32 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 0 0 20 20 20 20 20 20 20 20 obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained 59 59 59 59 59 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 50 50 50 50 50 50 50 50 50 50 obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of sintered alumina of 1 μm or 0 80 2 5 10 30 50 70 0 80 less*² (mass %) Amount of fused alumina of 85.56 5.56 83.56 80.56 75.56 55.56 35.56 15.56 85.56 5.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 176 144 184 176 172 173 171 162 184 136 After 2 hours 144 106 131 134 132 135 132 122 139 106 Bending strength after curing of 6 hours 0.4 1.1 0.8 0.9 0.9 0.9 1 1.2 0.4 1.3 (MPa) Bending strength after curing of 12 hours 0.6 1.5 1.1 1.2 1.2 1.4 1.4 1.5 0.8 1.6 (MPa) Bending strength after curing of 24 hours 1.8 2.3 1.8 1.9 2 2.1 2.2 2.2 1.5 2 (MPa) Wear amount in rotary corrosion test (mm) 6.5 6.1 6.1 5.9 5.9 5.7 5.7 5.8 5.9 6.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄ *²Mixing ratio with respect to monolithic refractory (total amount of binder and refractory aggregates)

TABLE 52 Example Example Example Example Example Example Reference Reference 288 289 290 291 292 293 Example 33 Example 34 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 14 14 14 14 14 14 14 14 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 14 14 14 14 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 12 12 12 12 12 12 12 12 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 Amount of sintered alumina of 1 μm or less*² 2 5 10 30 50 70 0 80 (mass %) Amount of fused alumina of 83.56 80.56 75.56 55.56 35.56 15.56 85.56 5.56 from 75 μm to 5 mm*² (mass %) 15 tap-flow value (mm) After mixing 184 181 177 174 171 163 186 142 After 2 hours 142 139 139 136 136 131 142 104 Bending strength after curing of 6 hours (MPa) 0.8 0.9 0.9 1 1 1.1 0.5 1.2 Bending strength after curing of 12 hours (MPa) 1.1 1.1 1.2 1.2 1.3 1.3 0.7 1.5 Bending strength after curing of 24 hours (MPa) 1.9 2 2.1 2.1 2.1 2.2 1.4 2.2 Wear amount in rotary corrosion test (mm) 6.1 5.9 5.8 5.7 5.7 5.8 6.3 5.9 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄ *²Mixing ratio with respect to monolithic refractory (total amount of binder and refractory aggregates)

The evaluation results are as shown in Tables 48 to 52. In Examples 258 to 293, the flow values suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 258 to 293 can be applied to furnaces with a large volume or the like. Furthermore, Examples 258 to 293 show favorable values in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 258 to 293 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, Examples 258 to 293 show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

On the other hand, in Reference Examples 23, 25, 27, 29, 31, and 33 including no ultrafine alumina powder with a particle diameter of 1 μm or less, it has been confirmed that the flexural strength after curing of 6 hours is low, it is difficult for a frame to be removed early, and the risk of explosion increases due to insufficient strength when the monolithic refractories are dried. In Reference Examples 24, 26, 28, 30, 32, and 34 including 80 mass % of ultrafine alumina powder with a particle diameter of 1 μm or less, the flow values deteriorated after 2 hours and a large amount of deterioration in the flow property after 2 hours occurred. Therefore, it has been confirmed that it is difficult for Reference Examples 24, 26, 28, 30, 32, and 34 to be applied to furnaces with a large volume or the like.

From these test results, in the binders for monolithic refractories according to the present invention, it has been confirmed that it is preferable to blend a refractory aggregate including an ultrafine alumina powder with a particle diameter of 1 μm or less in which an amount of the ultrafine alumina powder with a particle diameter of 1 μm or less is from 2 mass % to 70 mass %.

[12] Examples relating to a monolithic refractory using a varied amount of the binder for monolithic refractories according to the present invention

In Examples 294 to 337 and Reference Examples 35 to 44, in monolithic refractories manufactured using the binder according to the present invention, the same tests were performed with a varied amount of the binder in a case in which the total of the binder and refractory aggregates was made to be 100 mass %. In all tests, a binder including 40 mass % of various solid solutions and their mixture and 60 mass % of α-Al₂O₃ were used, wherein the solid solutions prepared such that raw materials had been controlled to obtain an X value of Ca_(x)Sr_(1-x)Al₂O₄ of 0.05, 0.30, or 0.95 and firing had been performed for 2 hours at the maximum temperature of 1500° C. Tables 53 to 58 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the various solid solutions and α-Al₂O₃, the amount of the binder added, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples.

TABLE 53 Refer- Refer- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ence ence ample ample ample ample ample ample ample ample Example Example 294 295 296 297 298 299 300 301 35 36 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of binder added (mass %) 0.2 0.3 0.5 5 10 12 16 20 25 0.2 15 tap-flow value (mass %) After mixing 161 163 171 168 170 174 176 172 163 161 After 2 hours 133 136 134 129 131 129 127 123 117 133 Bending strength after curing of 6 hours (MPa) 0.7 0.8 0.9 1.1 1.2 1.2 1.3 1.4 1.5 0.6 Bending strength after curing of 12 hours (MPa) 0.9 1.1 1.2 1.4 1.5 1.5 1.6 1.8 1.9 0.8 Bending strength after curing of 24 hours (MPa) 1.4 1.5 1.5 1.8 2 2.1 2.1 2.2 2.2 1.5 5 5 5.1 5.4 5.8 5.8 6 6.4 7.1 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 54 Refer- Refer- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ence ence Ex- ample ample ample ample ample ample ample Example Example ample 302 303 304 305 306 307 308 37 38 309 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 20 20 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of binder added (mass %) 0.3 0.5 5 10 12 16 20 25 0.2 0.3 15 tap-flow value (mass %) After mixing 162 167 169 172 170 174 168 169 159 162 After 2 hours 130 135 132 132 129 125 125 120 136 136 Bending strength after curing of 6 hours (MPa) 0.7 0.8 1 1.1 1.1 1.2 1.3 1.3 0.6 0.7 Bending strength after curing of 12 hours (MPa) 1 1.1 1.3 1.4 1.5 1.6 1.7 1.8 0.8 0.9 Bending strength after curing of 24 hours (MPa) 1.7 1.7 1.9 2 2.2 2.4 2.5 2.5 1.3 1.4 5.1 5.2 5.3 5.6 5.6 6.1 6.6 7.1 5 5.1 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 55 Refer- Refer- Ex- Ex- Ex- Ex- Ex- Ex- ence ence Ex- Ex- ample ample ample ample ample ample Example Example ample ample 310 311 312 313 314 315 39 40 316 317 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 20 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of binder added (mass %) 0.5 5 10 12 16 20 25 0.2 0.3 0.5 15 tap-flow value (mass %) After mixing 166 170 172 175 173 167 166 160 158 162 After 2 hours 139 135 136 133 133 127 125 132 134 132 Bending strength after curing of 6 hours (MPa) 0.8 0.9 1.1 1.1 1.2 1.3 1.5 0.5 0.7 0.8 Bending strength after curing of 12 hours (MPa) 0.9 1.2 1.5 1.5 1.6 1.8 1.8 0.8 0.9 0.9 Bending strength after curing of 24 hours (MPa) 1.4 1.8 2.2 2.3 2.3 2.3 2.4 1.2 1.4 1.5 5.2 5.6 5.8 6 6.2 6.6 7.2 5.2 5.2 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 56 Ex- Ex- Ex- Ex- Reference Ex- Ex- Ex- Ex- Example ample ample ample ample Example ample ample ample ample 318 319 320 321 322 41 323 324 325 326 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 03 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of binder added (mass %) 5 10 12 16 20 25 0.2 0.3 0.5 5 15 tap-flow value (mass %) After mixing 166 169 172 176 171 173 161 163 171 168 After 2 hours 130 137 134 131 129 128 133 136 134 129 Bending strength after curing of 6 hours (MPa) 0.9 1 1 1.1 1.2 1.2 0.7 0.7 0.8 1 Bending strength after curing of 12 hours (MPa) 1.1 1.3 1.3 1.4 1.5 1.6 0.9 1 1.1 1.2 Bending strength after curing of 24 hours (MPa) 2.2 2.4 2.5 2.5 2.6 2.7 1.5 1.6 1.6 1.8 5.6 5.9 6.1 6.2 6.7 7.3 5.1 5.2 5.1 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 57 Refer- Refer- Ex- Ex- Ex- Ex- ence ence Ex- Ex- Ex- Ex- ample ample ample ample Example Example ample ample ample ample 327 328 329 330 42 43 331 332 333 334 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 14 14 14 14 14 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 14 14 14 14 14 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 12 12 12 12 12 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Amount of binder added (mass %) 10 12 16 20 25 0.2 0.3 0.5 5 10 15 tap-flow value (mass %) After mixing 170 174 176 172 163 157 156 160 165 171 After 2 hours 131 129 127 123 117 133 135 134 133 135 Bending strength after curing of 6 hours (MPa) 1.1 1.1 1.2 1.3 1.4 0.6 0.7 0.8 1 1 Bending strength after curing of 12 hours (MPa) 1.4 1.5 1.5 1.9 1.9 0.9 1 1.1 1.2 1.3 Bending strength after curing of 24 hours (MPa) 2 2.1 2.2 2.3 2.4 1.2 1.4 1.5 2 2.2 5.7 5.7 6.1 6.5 7.1 5.1 5.1 5.1 5.5 5.9 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 58 Example Example Example Reference 335 336 337 Example 44 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 12 12 12 12 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of α-Al₂O₃ (mass %) *¹ 60 60 60 60 Amount of binder added (mass %) 12 16 20 25 15 tap-flow value After mixing 173 173 170 169 (mass %) After 2 hours 130 135 129 127 Bending strength after curing of 6 hours (MPa) 1.1 1.2 1.2 1.2 Bending strength after curing of 12 hours (MPa) 1.4 1.5 1.6 1.6 Bending strength after curing of 24 hours (MPa) 2.3 2.4 2.4 2.5 5.9 6.3 6.8 7.1 Note) *¹ Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Tables 53 to 58. In Examples 294 to 337, the flow values suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 294 to 337 can be applied to furnaces with a large volume or the like. Furthermore, Examples 294 to 337 show favorable values in the flexural strength after curing of 6, 12, and 24 hours. In particular, Examples 294 to 337 show larger values in the flexural strength after curing of 6 hours, and therefore it has been clarified that Examples 294 to 337 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, Examples 294 to 337 show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

On the other hand, in Reference Examples 36, 38, 40, and 43 in which an amount of the binder added was 0.2 mass %, it has been confirmed that the flexural strength after curing of 6 hours is low, it is difficult for a frame to be removed early, and the risk of explosion increases due to insufficient strength when the monolithic refractories are dried. In Reference Examples 35, 37, 39, 41, 42, and 44 in which an amount of the binder added was 25 mass %, it has been confirmed that, compared to other cases, Reference Examples 35, 37, 39, 41, 42, and 44 show an increase in the wear amount in the rotary corrosion test using slag and degradation in the slag resistance at a high temperature.

In Examples in which an amount of the binder added was from 0.5 mass % to 12 mass %, it has been confirmed that Examples are excellent in terms of both of the cured strength and the wear amount in the rotary corrosion test using slag.

From these test results, it has been confirmed that the amount of the binder for monolithic refractories according to the present invention is preferably from 0.3 mass % to 20 mass %, and further preferably from 0.5 mass % to 12 mass % with respect to 100 mass % of the total amount of the binder for monolithic refractories and the refractory aggregates.

[13] Examples relating to a monolithic refractory into which at least one of a dispersant, a hardening retardant, and a hardening accelerator is added

In Examples 338 to 515, monolithic refractories were manufactured by using a binder including 40 mass % of various solid solutions and their mixture and 60 mass % of α-Al₂O₃, wherein the solid solutions prepared such that raw materials had been controlled to obtain an X value of Ca_(x)Sr_(1-x)Al₂O₄ of 0.05, 0.30, or 0.95 and firing had been performed for 2 hours at the maximum temperature of 1500° C., and blending a predetermined amount of at least one kind of a variety of dispersants, hardening retardants and hardening accelerators in outer percentage, and then the tests were performed. In addition, in Comparative Examples 31 to 47, monolithic refractories were manufactured by using a binder including no Sr components and blending at least one kind of a dispersant, a hardening retardant and a hardening accelerator in the same manner, and then the tests were performed. Further, when blending a dispersant, a hardening retardant, or a dispersant and a hardening retardant, the amount of water added was reduced to 6.2 mass % with respect to 100 mass % of the mixture of the binder and refractory aggregates, and then the test was performed. In addition, when blending only a hardening accelerator, as usual, 6.8 mass % of water was added and the test was performed. A powder dispersant, a hardening retardant, and a hardening accelerator were used after being blended with the binder and refractory aggregate using an omni mixer. For liquid dispersants, the mass of solid components included was considered as the amount added, and adjustment was performed so as to obtain a predetermined amount of water by reducing from the amount of water to be added by the mass portion of the solvent parts. In addition, liquid dispersants were used after being blended with mixing water.

Meanwhile, in the embodiments, a sodium polyacrylate reagent, which is a polycarboxylic acid-based dispersant, was used as the dispersant A; “TIGHTLOCK” (trade name, manufactured by Kao Corporation), which is a polyether-based dispersant, was used as the dispersant B; sodium tripolyphosphate (primary reagent), which is a phosphate-based dispersant, was used as the dispersant C; trisodium citrate dihydrate (primary reagent), which is an oxycarboxylic acid, was used as the dispersant D; “FT-3S” (with a solid content of 33 mass %) (trade name, manufactured by Grace Chemical Co., Ltd.), which is a melamine-based dispersant, was used as the dispersant E; “MIGHTY 150” (with a solid content of 40 mass %) (trade name, manufactured by Kao Corporation), which is a naphthalene-based dispersant, was used as the dispersant F; “VANILLEX HW” (trade name, manufactured by Nippon Paper Chemicals Co., Ltd.), which is a lignin-based dispersant, was used as the dispersant G; boric acid (special grade chemical), which is one of boric acid groups, was used as the hardening retardant a; sodium silicofluoride (special grade chemical), which is a silicofluoride, was used as the hardening retardant b; lithium citrate (primary reagent), which is one of salts of alkaline metals, was used as the hardening accelerator a; and sodium aluminate (primary reagent), which is one of aluminates, was used as the hardening accelerator 13.

Tables 59 to 78 show the compositions of the solid solutions, the crystallite diameters of the solid solutions, the blending ratio of the various solid solutions and CaAl₂O₄ and α-Al₂O₃ for comparison, the type and amount added of the dispersant, the type and amount added of the hardening retardant, the type and amount added of the hardening accelerator, and the measurement results of flow value and flexural strength after curing and results of the rotary corrosion test of the monolithic refractory in each of the Examples. In the tables, the amounts of the dispersant, the hardening retardant, and the hardening accelerator used are represented by the ratio to the total amount of the binders and the refractory aggregates.

TABLE 59 Ex- Ex- Ex- Ex- Ex Ex- Ex- Ex- Example Example ample ample ample ample ample ample ample ample 338 339 340 341 342 343 344 345 346 347 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant A A A B B B C C C D Amount of dispersant added (mass %) 0.05 0.1 0.3 0.05 0.1 0.3 0.05 0.1 0.3 0.05 Type of hardening retardant — — — — — — — — — — Amount of hardening retardant added (mass %) — — — — — — — — — — Type of hardening accelerator — — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — — 15 tap-flow value (mm) After mixing 160 172 189 171 182 194 146 153 159 143 After 2 hours 120 122 126 127 131 143 118 122 120 122 Bending strength after curing of 6 hours (MPa) 1.4 1.5 1.6 1.4 1.3 1 1.4 1.5 1.5 1.3 Bending strength after curing of 12 hours (MPa) 1.8 1.8 1.9 1.9 1.7 1.4 1.8 1.9 1.9 1.6 Bending strength after curing of 24 hours (MPa) 2.4 2.4 2.5 22 2.1 1.9 2.4 2.3 2.4 2.1 Wear amount in rotary corrosion test (mm) 5.3 5.2 5.2 5.3 5.3 5.5 5.4 5.3 5.3 5.6 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 60 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Example Example ample ample ample ample ample ample ample ample 348 349 350 351 352 353 354 355 356 357 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant D D E E E F F F G G Amount of dispersant added (mass %) 0.1 0.3 0.05 0.1 0.3 0.05 0.1 0.3 0.05 0.1 Type of hardening retardant — — — — — — — — — — Amount of hardening retardant added (mass %) — — — — — — — — — — Type of hardening accelerator — — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — — 15 tap-flow value (mm) After mixing 149 152 144 146 153 142 151 151 151 157 After 2 hours 127 130 117 121 123 116 118 123 122 128 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.4 1.5 1.4 1.2 1.3 1.3 1.4 1.4 Bending strength after curing of 12 hours (MPa) 1.9 2 1.8 1.9 1.8 1.6 1.7 1.6 1.7 1.8 Bending strength after curing of 24 hours (MPa) 2.5 2.5 2.2 2.4 2.4 2 2.2 2.3 2.1 2.3 Wear amount in rotary corrosion test (mm) 5.4 5.4 5.6 5.5 5.4 5.3 5.4 5.3 5.4 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 61 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Example Example ample ample ample ample ample ample ample ample 358 359 360 361 362 363 364 365 366 367 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant G — — — — — — — — — Amount of dispersant added (mass %) 0.3 — — — — — — — — — Type of hardening retardant — a a a b b b — — — Amount of hardening retardant added (mass %) — 0.01 0.05 0.2 0.01 0.05 0.2 — — — Type of hardening accelerator — — — — — — — α α α Amount of hardening accelerator added (mass %) — — — — — — — 0.01 0.05 0.2 15 tap-flow value (mm) After mixing 156 151 161 163 145 141 140 169 174 164 After 2 hours 124 121 124 128 124 129 130 130 123 117 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.6 1.6 1.2 1.1 0.9 1.5 1.5 1.7 Bending strength after curing of 12 hours (MPa) 1.9 1.9 1.9 2 1.6 1.5 1.2 1.7 1.8 1.9 Bending strength after curing of 24 hours (MPa) 2.3 2.2 2.2 2.1 2.3 2.2 1.9 2 2.1 2.1 Wear amount in rotary corrosion test (mm) 5.2 5.4 5.3 5.4 5.3 5.4 5.5 5.8 5.9 5.8 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 62 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample ample ample 368 369 370 371 372 373 374 375 376 377 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant — — — A A A A A A A Amount of dispersant added (mass %) — — — 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Type of hardening retardant — — — a a a b b b — Amount of hardening retardant added (mass %) — — — 0.01 0.05 0.2 0.01 0.05 0.2 — Type of hardening accelerator β β β — — — — — — α Amount of hardening accelerator added (mass %) 0.01 0.05 0.2 — — — — — — 0.01 15 tap-flow value (mm) After mixing 173 182 180 171 167 166 169 163 162 173 After 2 hours 132 129 115 127 128 131 133 132 136 125 Bending strength after curing of 6 hours (MPa) 1.4 1.6 1.7 1.4 1.3 1.3 1.3 1.2 1 1.8 Bending strength after curing of 12 hours (MPa) 1.7 1.9 2 1.9 1.7 1.6 1.6 1.6 1.5 2.1 Bending strength after curing of 24 hours (MPa) 2 2.2 2.1 2.3 2.2 2.3 2.1 2.2 2.2 2.5 Wear amount in rotary corrosion test (mm) 5.8 5.9 6 5.2 5.4 5.4 5.3 5.4 5.2 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 63 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample ample ample 378 379 380 381 382 383 384 385 386 387 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant A A A A A — — — — — Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 — — — — — Type of hardening retardant — — — — — a a a a a Amount of hardening retardant added (mass %) — — — — — 0.05 0.05 0.05 0.05 0.05 Type of hardening accelerator α α β β β α α α β β Amount of hardening accelerator added 0.05 0.2 0.01 0.05 0.2 0.01 0.05 0.2 0.01 0.05 (mass %) 15 tap-flow value (mm) After mixing 175 168 169 171 164 145 142 139 142 144 After 2 hours 121 117 124 121 118 134 128 118 131 123 Bending strength after curing of 6 hours (MPa) 1.9 1.9 1.8 1.9 2 1.5 1.6 1.8 1.7 1.8 Bending strength after curing of 12 hours (MPa) 2.2 2.3 2.1 2.3 2.3 1.9 2 2.2 2.1 2.2 Bending strength after curing of 24 hours (MPa) 2.5 2.4 2.6 2.7 2.7 2.4 2.3 2.4 2.5 2.5 Wear amount in rotary corrosion test (mm) 5.2 5.3 5.2 5.3 5.2 5.4 5.3 5.3 5.4 5.4 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 64 Com- Com- Com- Com- Com- Com- Com- parative parative parative parative parative parative parative Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample ample ample 388 389 390 31 32 33 34 35 36 37 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 — — — — — — — Crystallite diameter of solid solution obtained by 59 59 59 — — — — — — — dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 — — — — — — — dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 — — — — — — — Crystallite diameter of solid solution obtained by 54 54 54 — — — — — — — dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 — — — — — — — dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 — — — — — — — Crystallite diameter of solid solution obtained by 50 50 50 — — — — — — — dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 — — — — — — — dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — 40 40 40 40 40 40 40 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant — A A A B C D E F G Amount of dispersant added (mass %) — 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Type of hardening retardant a a a — — — — — — — Amount of hardening retardant added (mass %) 0.05 0.05 0.05 — — — — — — — Type of hardening accelerator β α β — — — — — — — Amount of hardening accelerator added (mass %) 0.2 0.05 0.05 — — — — — — — 15 tap-flow value (mm) After mixing 145 173 176 173 182 170 172 166 164 168 After 2 hours 116 137 134 137 142 131 129 131 125 132 Bending strength after curing of 6 hours (MPa) 2 1.8 2 0.5 0.3 0.5 0.6 0.4 0.6 0.5 Bending strength after curing of 12 hours (MPa) 2.2 2.2 2.2 0.8 0.6 1 1.1 0.8 1 0.9 Bending strength after curing of 24 hours (MPa) 2.6 2.6 2.6 1.4 1.2 1.7 1.6 1.3 1.5 1.6 Wear amount in rotary corrosion test (mm) 5.3 5.1 5.2 7.4 7.7 7.4 7.5 7.6 7.5 7.6 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 65 Com- Com- Com- Com- Com- Com- Com- Com- Com- parative parative parative parative parative parative parative parative parative Comparative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Example 38 ple 39 ple 40 ple 41 ple 42 ple 43 ple 44 ple 45 ple 46 ple 47 X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — — — — — — Crystallite diameter of solid solution obtained by — — — — — — — — — — dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by — — — — — — — — — — dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — — — — — — Crystallite diameter of solid solution obtained by — — — — — — — — — — dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by — — — — — — — — — — dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ — — — — — — — — — — Crystallite diameter of solid solution obtained by —— — — — — — — — — dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by — — — — — — — — — — dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) 40 40 40 40 40 40 40 40 40 40 Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 Type of dispersant — — — — A A A A A A Amount of dispersant added (mass %) — — — — 0.1 0.1 0.1 0.1 0.1 0.1 Type of hardening retardant a b — — a b — — a b Amount of hardening retardant added (mass %) 0.05 0.05 — — 0.05 0.05 — — 0.05 0.05 Type of hardening accelerator — — α β — — α β α β Amount of hardening accelerator added (mass %) — — 0.05 0.05 — — 0.05 0.05 0.05 0.05 15 tap-flow value (mm) After mixing 151 147 153 150 167 161 164 173 168 173 After 2 hours 126 127 121 119 139 147 119 123 126 119 Bending strength after curing of 6 hours (MPa) 0.4 0.3 0.9 0.8 0.4 0.3 1 1 0.7 0.7 Bending strength after curing of 12 hours (MPa) 0.7 0.5 1.4 1.4 0.7 0.6 1.5 1.4 1.3 1.2 Bending strength after curing of 24 hours (MPa) 1.1 0.9 1.6 1.5 1.2 0.9 1.7 1.6 1.7 1.6 Wear amount in rotary corrosion test (mm) 7.8 8.1 8.3 8.2 7.5 7.9 7.5 7.6 7.4 7.6 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 66 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple ple ple 391 392 393 394 395 396 397 398 399 400 401 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 59 59 59 59 59 59 59 59 59 59 59 obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 50 50 50 50 50 50 50 50 50 50 50 obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained 0 0 0 0 0 0 0 0 0 0 0 by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 60 Type of dispersant A A A B B B C C C D D Amount of dispersant added (mass %) 0.05 0.1 0.3 0.05 0.1 0.3 0.05 0.1 0.3 0.05 0.1 Type of hardening retardant — — — — — — — — — — — Amount of hardening retardant added — — — — — — — — — — — (mass %) Type of hardening accelerator — — — — — — — — — — — Amount of hardening accelerator added — — — — — — — — — — — (mass %) 15 tap-flow value (mm) After mixing 158 170 173 167 180 186 148 151 157 151 153 After 2 hours 123 128 133 128 134 143 123 122 124 124 121 Bending strength after curing of 6 hours 1.3 1.4 1.4 1.3 1.3 0.9 1.2 1.2 1.1 12 1.3 (MPa) Bending strength after curing of 12 hours 1.6 1.7 1.7 1.7 1.7 1.2 1.7 1.5 1.6 1.6 1.6 (MPa) Bending strength after curing of 24 hours 2.7 2.6 2.6 2.5 2.4 2.5 2.5 2.3 2.3 2.4 2.5 (MPa) Wear amount in rotary corrosion test (mm) 5.3 5.4 5.4 5.5 5.3 5.3 5.5 5.5 5.4 5.3 5.5 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 67 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple ple ple 402 403 404 405 406 407 408 409 410 411 412 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 59 59 59 59 59 59 59 59 59 59 59 obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 50 50 50 50 50 50 50 50 50 50 50 obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 60 Type of dispersant D E E E F F F G G G — Amount of dispersant added (mass %) 0.3 0.05 0.1 0.3 0.05 0.1 0.3 0.05 0.1 0.3 — Type of hardening retardant — — — — — — — — — — a Amount of hardening retardant added — — — — — — — — — — 0.01 (mass %) Type of hardening accelerator — — — — — — — — — — — Amount of hardening accelerator added — — — — — — — — — — — (mass %) 15 tap-flow value (mm) After mixing 155 151 153 159 150 153 152 156 161 166 147 After 2 hours 127 121 124 120 121 125 122 124 128 131 126 Bending strength after curing of 6 hours 1.3 1.4 1.4 1.3 1.3 1.2 1.2 1.3 1.3 1.2 1.3 (MPa) Bending strength after curing of 12 hours 1.8 1.8 1.7 1.6 1.6 1.7 1.7 1.8 1.7 1.7 1.6 (MPa) Bending strength after curing of 24 hours 2.5 2.6 2.4 2.4 2.3 2.4 2.4 2.5 2.6 2.4 2.5 (MPa) Wear amount in rotary corrosion test (mm) 5.5 5.4 5.3 5.4 5.4 5.5 5.4 5.4 5.4 5.5 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 68 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple ple ple 413 414 415 416 417 418 419 420 421 422 423 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 59 59 59 59 59 59 59 59 59 59 59 obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 03 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 40 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 50 50 50 50 50 50 50 50 50 50 50 obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 60 60 Type of dispersant — — — — — — — — — — — Amount of dispersant added (mass %) — — — — — — — — — — — Type of hardening retardant a a b b b — — — — — — Amount of hardening retardant added 0.05 0.2 0.01 0.05 0.2 — — — — — — (mass %) Type of hardening accelerator — — — — — α α α β β β Amount of hardening accelerator added — — — — — 0.01 0.05 0.2 0.01 0.05 0.2 (mass %) 15 tap-flow value (mm) After mixing 153 152 143 140 142 166 172 174 173 176 175 After 2 hours 131 132 125 130 135 127 126 121 125 122 118 Bending strength after curing of 6 hours 1.3 1.2 1.1 1 0.8 1.4 1.4 1.5 1.3 1.4 1.5 (MPa) Bending strength after curing of 12 hours 1.5 1.5 1.4 1.3 1.1 1.7 1.8 1.8 1.6 1.7 1.9 (MPa) Bending strength after curing of 24 hours 2.3 2.3 2.5 2.4 2.2 2.5 2.4 2.2 2.3 2.3 2.2 (MPa) Wear amount in rotary corrosion test (mm) 5.4 5.4 5.4 5.5 5.3 5.9 6 5.8 5.9 6 5.9 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 69 Example Example Example Example Example Example Example Example Example Example Example 424 425 426 427 428 429 430 431 432 433 434 X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution 59 59 59 59 59 59 59 59 59 59 59 obtained by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution 0 0 0 0 0 0 0 0 0 0 0 obtained by dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution 54 54 54 54 54 54 54 54 54 54 54 obtained by dissolving Ca components β-SrAl₂O₄ (nm) Blending ratio of solid solution 40 40 40 40 40 40 40 40 40 40 40 obtained by dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution 50 50 50 50 50 50 50 50 50 50 50 obtained by dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution 0 0 0 0 0 0 0 0 0 0 0 obtained by dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %)                       Blending ratio of α-Al₂O₃ (mass %) *1 60 60 60 60 60 60 60 60 60 60 60 Type of dispersant A A A A A A A A A A A Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Type of hardening retardant a a a b b b           Amount of hardening retardant 0.01 0.05 0.2 0.01 0.05 0.2           added (mass %) Type of hardening accelerator             α α α β β Amount of hardening accelerator             0.01 0.05 0.2 0.01 0.05 added (mass %) 15 tap-flow value (mm) After mixing 169 167 162 163 160 163 170 172 166 173 175 After 2 hours 131 135 140 133 135 139 129 124 122 124 122 Bending strength after curing of 1.3 1.2 1.2 1.3 1.1 0.9 1.7 1.8 1.8 1.6 1.7 6 hours (MPa) Bending strength after curing of 1.8 1.6 1.5 1.6 1.4 1.3 2 2.1 2.2 1.9 2 12 hours (MPa) Bending strength after curing of 2.5 2.4 2.3 2.4 2.3 2.3 2.6 2.5 2.3 2.6 2.6 24 hours (MPa) Wear amount in rotary corrosion 5.3 5.3 5.4 5.3 5.3 5.3 5.4 5.3 5.5 5.4 5.3 test (mm) Note) *1 Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 70 Example Example Example Example Example Example Example Example Example 435 436 437 438 439 440 441 442 443 X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained 59 59 59 59 59 59 59 59 59 by dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 40 40 40 40 40 40 40 40 40 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1-x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained 50 50 50 50 50 50 50 50 50 by dissolving Sr components CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Sr components in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %)                   Blending ratio of α-Al₂O₃ (mass %) *1 60 60 60 60 60 60 60 60 60 Type of dispersant A             A A Amount of dispersant added (mass %) 0.1             0.1 0.1 Type of hardening retardant   a a a a a a a a Amount of hardening retardant added (mass %)   0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Type of hardening accelerator β α α α β β β α β Amount of hardening accelerator added (mass %) 0.2 0.01 0.05 0.2 0.01 0.05 0.2 0.05 0.05 15 tap-flow value (mm) After mixing 168 147 142 143 147 153 156 176 172 After 2 hours 118 137 131 125 134 127 121 141 138 Bending strength after curing of 6 hours (MPa) 1.7 1.4 1.5 1.7 1.5 1.6 1.7 1.7 1.8 Bending strength after curing of 12 hours (MPa) 2.1 1.8 1.8 2 1.8 1.8 2 2 2.1 Bending strength after curing of 24 hours (MPa) 2.5 2.6 2.6 2.5 2.6 2.5 2.6 2.7 2.6 Wear amount in rotary corrosion test (mm) 5.3 5.3 5.4 5.5 5.3 5.4 5.5 5.3 5.2 Note) *1 Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 71 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 444 445 446 447 448 449 450 451 452 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant A B C D E F G — — Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 — — Type of hardening retardant — — — — — — — a b Amount of hardening retardant added (mass %) — — — — — — — 0.05 0.05 Type of hardening accelerator — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — 15 tap-flow value (mm) After mixing 170 179 157 152 152 159 160 148 148 After 2 hours 125 133 130 131 124 131 131 128 131 Bending strength after curing of 6 hours (MPa) 1.4 1.1 1.3 1.3 1.3 1.1 1.4 1.2 1 Bending strength after curing of 12 hours (MPa) 1.8 1.4 1.7 1.7 1.8 1.5 1.7 1.5 1.3 Bending strength after curing of 24 hours (MPa) 2.6 2.2 2.4 2.6 2.5 2.5 2.6 2.4 2.2 Wear amount in rotary corrosion test (mm) 5.4 5.3 5.3 5.4 5.4 5.3 5.3 5.3 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 72 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 453 454 455 456 457 458 459 460 461 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant — — A A A A — — A Amount of dispersant added (mass %) — — 0.1 0.1 0.1 0.1 — — 0.1 Type of hardening retardant — — a b — — a a a Amount of hardening retardant added (mass %) — — 0.05 0.05 — — 0.05 0.05 0.05 Type of hardening accelerator α β — — α β α β α Amount of hardening accelerator added (mass %) 0.05 0.05 — — 0.05 0.05 0.05 0.05 0.05 15 tap-flow value (mm) After mixing 169 174 166 166 172 175 140 152 170 After 2 hours 129 130 132 134 126 125 123 130 135 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.3 1.1 1.7 1.7 1.6 1.8 1.5 Bending strength after curing of 12 hours (MPa) 1.8 1.9 1.6 1.5 2.1 2.1 1.9 2.1 2 Bending strength after curing of 24 hours (MPa) 2.3 2.3 2.5 2.5 2.6 2.7 2.6 2.6 2.5 Wear amount in rotary corrosion test (mm) 5.8 5.7 5.4 5.3 5.2 5.2 5.4 5.3 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 73 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 462 463 464 465 466 467 468 469 470 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant A B C D E F G — — Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 — — Type of hardening retardant — — — — — — — a b Amount of hardening retardant added (mass %) — — — — — — — 0.05 0.05 Type of hardening accelerator — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — 15 tap-flow value (mm) After mixing 163 179 160 157 158 159 162 146 151 After 2 hours 128 136 130 132 132 125 131 126 131 Bending strength after curing of 6 hours (MPa) 1.1 0.9 1.1 1.1 1 1.2 1 1 0.9 Bending strength after curing of 12 hours (MPa) 1.6 1.3 1.5 1.5 1.4 1.5 1.4 1.3 1.2 Bending strength after curing of 24 hours (MPa) 2.7 2.3 2.6 2.7 2.5 2.7 2.6 2.5 2.5 Wear amount in rotary corrosion test (mm) 5.3 5.3 5.3 5.4 5.5 5.3 5.4 5.4 5.5 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 74 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 471 472 473 474 475 476 477 478 479 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant — — A A A A — — A Amount of dispersant added (mass %) — — 0.1 0.1 0.1 0.1 — — 0.1 Type of hardening retardant — — a b — — a a a Amount of hardening retardant added (mass %) — — 0.05 0.05 — — 0.01 0.01 0.01 Type of hardening accelerator α β — — α β α β α Amount of hardening accelerator added (mass %) 0.05 0.05 — — 0.05 0.05 0.05 0.05 0.05 15 tap-flow value (mm) After mixing 160 164 166 160 171 171 146 153 162 After 2 hours 122 126 131 133 125 128 131 126 132 Bending strength after curing of 6 hours (MPa) 1.5 1.5 1.1 0.9 1.6 1.7 1.5 1.7 1.5 Bending strength after curing of 12 hours (MPa) 1.9 2 1.4 1.3 2 2 1.7 2.1 1.8 Bending strength after curing of 24 hours (MPa) 2.4 2.6 2.5 2.6 2.7 2.6 2.7 2.7 2.7 Wear amount in rotary corrosion test (mm) 5.9 5.7 5.2 5.3 5.3 5.2 5.5 5.3 5.2 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 75 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 480 481 482 483 484 485 486 487 488 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant A B C D E F G — — Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 — — Type of hardening retardant — — — — — — — a b Amount of hardening retardant added (mass %) — — — — — — — 0.05 0.05 Type of hardening accelerator — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — 15 tap-flow value (mm) After mixing 168 174 161 159 162 157 162 147 146 After 2 hours 126 134 133 131 129 131 137 131 136 Bending strength after curing of 6 hours (MPa) 1.3 1.2 1.2 1.1 1.2 1 1.2 1.1 1 Bending strength after curing of 12 hours (MPa) 1.7 1.5 1.6 1.6 1.6 1.4 1.6 1.4 1.3 Bending strength after curing of 24 hours (MPa) 2.6 2.4 2.5 2.6 2.7 2.5 2.5 2.5 2.4 Wear amount in rotary corrosion test (mm) 5.5 5.3 5.4 5.6 5.4 5.5 5.5 5.3 5.4 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 76 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 489 490 491 492 493 494 495 496 497 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 20 20 20 20 20 20 20 20 20 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 0 0 0 0 0 0 0 0 0 dissolving Sr componentst in CaA₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant — — A A A A — — A Amount of dispersant added (mass %) — — 0.1 0.1 0.1 0.1 — — 0.1 Type of hardening retardant — — a b — — a a a Amount of hardening retardant added (mass %) — — 0.05 0.05 — — 0.05 0.05 0.05 Type of hardening accelerator α β — — α β α β α Amount of hardening accelerator added (mass %) 0.05 0.05 — — 0.05 0.05 0.05 0.05 0.05 15 tap-flow value (mm) After mixing 169 169 172 169 174 172 148 155 173 After 2 hours 129 127 138 135 130 133 127 134 139 Bending strength after curing of 6 hours (MPa) 1.3 1.3 1.2 1.1 1.5 1.6 1.4 1.6 1.4 Bending strength after curing of 12 hours (MPa) 1.7 1.7 1.5 1.4 1.9 1.9 1.8 2 1.9 Bending strength after curing of 24 hours (MPa) 2.2 2.3 2.6 2.6 2.6 2.6 2.4 2.5 2.6 Wear amount in rotary corrosion test (mm) 5.9 5.8 5.3 5.5 5.3 5.4 5.6 5.5 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 77 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 498 499 500 501 502 503 504 505 506 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 14 14 14 14 14 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 14 14 14 14 14 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 12 12 12 12 12 12 12 12 12 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₄ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant A B C D E F G — — Amount of dispersant added (mass %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 — — Type of hardening retardant — — — — — — — a b Amount of hardening retardant added (mass %) — — — — — — — 0.05 0.05 Type of hardening accelerator — — — — — — — — — Amount of hardening accelerator added (mass %) — — — — — — — — — 15 tap-flow value (mm) After mixing 167 171 160 155 155 156 157 146 148 After 2 hours 129 135 132 134 130 128 128 129 131 Bending strength after curing of 6 hours (MPa) 1.3 1.1 1.3 1.2 1.1 1.3 1.1 1.1 0.8 Bending strength after curing of 12 hours (MPa) 1.7 1.4 1.6 1.6 1.5 1.7 1.6 1.5 1.2 Bending strength after curing of 24 hours (MPa) 2.6 2.4 2.6 2.6 2.4 2.6 2.6 2.5 2.1 Wear amount in rotary corrosion test (mm) 5.4 5.3 5.2 5.4 5.2 5.3 5.4 5.3 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

TABLE 78 Exam- Exam- Exam- ple Example ple Example ple Example Example Example Example 507 508 509 510 511 512 513 514 515 X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Crystallite diameter of solid solution obtained by 59 59 59 59 59 59 59 59 59 dissolving Ca components in α-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 14 14 14 14 14 dissolving Ca components in α-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Crystallite diameter of solid solution obtained by 54 54 54 54 54 54 54 54 54 dissolving Ca components in β-SrAl₂O₄ (nm) Blending ratio of solid solution obtained by 14 14 14 14 14 14 14 14 14 dissolving Ca components in β-SrAl₂O₄ (mass %) X value of Ca_(x)Sr_(1−x)Al₂O₄ 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 Crystallite diameter of solid solution obtained by 50 50 50 50 50 50 50 50 50 dissolving Sr components in CaAl₂O₄ (nm) Blending ratio of solid solution obtained by 12 12 12 12 12 12 12 12 12 dissolving Sr componentst in CaAl₂O₄ (mass %) Blending ratio of CaAl₂O₄ (mass %) — — — — — — — — — Blending ratio of α-Al₂O₃ (mass %)*¹ 60 60 60 60 60 60 60 60 60 Type of dispersant — — A A A A — — A Amount of dispersant added (mass %) — — 0.1 0.1 0.1 0.1 — — 0.1 Type of hardening retardant — — a b — — a a a Amount of hardening retardant added (mass %) — — 0.05 0.05 — — 0.01 0.01 0.01 Type of hardening accelerator α β — — α β α β α Amount of hardening accelerator added (mass %) 0.05 0.05 — — 0.05 0.05 0.05 0.05 0.05 15 tap-flow value (mm) After mixing 167 169 160 162 167 177 144 150 167 After 2 hours 129 126 133 136 128 134 133 126 134 Bending strength after curing of 6 hours (MPa) 1.5 1.4 1.1 0.9 1.6 1.8 1.5 1.7 1.5 Bending strength after curing of 12 hours (MPa) 1.7 1.9 1.4 1.3 2.1 2.1 1.8 2 1.9 Bending strength after curing of 24 hours (MPa) 2.6 2.5 2.6 2.4 2.7 2.6 2.5 2.5 2.6 Wear amount in rotary corrosion test (mm) 5.8 5.7 5.3 5.3 5.2 5.3 5.3 5.4 5.3 Note) *¹Al₂O₃ other than solid solution and CaAl₂O₄

The evaluation results are as shown in Tables 59 to 78. In the cases of Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 in which a dispersant and/or a hardening retardant were used, regardless of the reduced amount of water added to monolithic refractories, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 can be applied to furnaces with a large volume or the like. Furthermore, Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 show larger values than Comparative Examples 31 to 39, 42, and 43 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In addition, by reducing the amount of water added, compared to Examples in which the same binder was used with the ordinary amount of water added, Examples 338 to 364, 371 to 376, 391 to 417, 424 to 429, 444 to 452, 455, 456, 462 to 470, 473, 474, 480 to 488, 491, 492, 498 to 506, 505, and 506 show an increase in the cured flexural strength and degradation in the wear amount in the rotary corrosion test using slag.

In Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 using only a hardening accelerator, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 can be applied to furnaces with a large volume or the like. Furthermore, Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 show larger values than Comparative Examples 40 and 41 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 including a hardening accelerator added, the cured flexural strength was further increased after 6 hours and 12 hours compared to Examples including no hardening accelerator added, which clarified that Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 are superior in terms of early strength developing property. In addition, the wear amount became almost the same as that of cases including no additive in the rotary corrosion test using slag, which clarified that Examples 365 to 370, 418 to 423, 453, 454, 471, 472, 489, 490, 507, and 508 are excellent in terms of slag resistance at a high temperature.

In Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 using a hardening accelerator and furthermore at least either a dispersant or a hardening retardant, regardless of the reduced amount of water added to monolithic refractories, the flow values of the monolithic refractories suitable for pouring were obtained 2 hours after the start of mixing. Therefore, it has been confirmed that Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 can be applied to furnaces with a large volume or the like. Furthermore, Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 show larger values than Comparative Examples 44 to 47 in the flexural strength after curing of 6, 12, and 24 hours, and therefore it has been clarified that Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 are excellent in terms of cured strength developing property. In particular, the flexural strength after curing of 6 hours is remarkably greater compared to those of the Comparative Examples, and therefore it has been confirmed that Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 are excellent in terms of early strength developing property. Furthermore, it has been clarified that, compared to Comparative Examples, Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 clearly show small wear amounts in the rotary corrosion test using slag and are excellent in terms of slag resistance at a high temperature.

In Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515, the cured flexural strength further increased after 6 hours and 12 hours compared to Examples including at least either a dispersant or a hardening retardant, and no hardening accelerator added, which clarified that Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 are superior in terms of early strength developing property. In addition, the wear amount became almost the same in the rotary corrosion test using slag, which clarified that Examples 377 to 390, 430 to 443, 457 to 461, 475 to 479, 493 to 497, and 511 to 515 are excellent in terms of slag resistance at a high temperature.

As described above, the binders for monolithic refractories according to the present invention of all Examples obtained more satisfactory flow property suitable for pouring even after a long period of time has elapsed after mixing, were superior to Comparative Examples in terms of early strength developing property, thereby obtaining excellent construction performance. In addition, all Examples obtained more satisfactory slag resistance at 1600° C. than the Comparative Examples, which clarified that the tolerance at places that come into contact with molten iron or slag are improved.

INDUSTRIAL APPLICABILITY

According to the prevention, a binder for monolithic refractories having excellent corrosion resistance with respect to slag or molten iron and excellent characteristics in the early development of hardened strength and the stability thereof, compared to binders such as alumina cement in the conventional technology; a monolithic refractory using the binder; and a construction method of the monolithic refractory, can be provided.

REFERENCE SYMBOL LIST

-   -   1: REFRACTORY (TEST SPECIMEN)     -   2: PROTECTION PLATE     -   3: BURNER     -   4: SLAG     -   5: FILLING MATERIAL 

The invention claimed is:
 1. A binder for monolithic refractories comprising a solid solution obtained by dissolving Ca components in α-SrAl₂O₄ or β-SrAl₂O₄, wherein when the Ca components are dissolved in the α-SrAl₂O₄, a crystallite diameter of the solid solution is from 40 nm to 75 nm, and when the Ca components are dissolved in the β-SrAl₂O₄, a crystallite diameter of the solid solution is from 35 nm to 70 nm.
 2. The binder for monolithic refractories according to claim 1, wherein an amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ or the β-SrAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.
 3. The binder for monolithic refractories according to claim 1, further comprising, as a mixture, a solid solution obtained by dissolving Sr components in CaAl₂O₄, wherein a crystallite diameter of the solid solution is from 25 nm to 60 nm.
 4. The binder for monolithic refractories according to claim 3, wherein an amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ or the β-SrAl₂O₄ and the solid solution obtained by dissolving Sr components in the CaAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.
 5. The binder for monolithic refractories according to claim 1, wherein both of a solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ and a solid solution obtained by dissolving Ca components in the β-SrAl₂O₄ are included as a mixture.
 6. The binder for monolithic refractories according to claim 5, wherein a total amount of both of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄ and the solid solution obtained by dissolving Ca components in the β-SrAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.
 7. The binder for monolithic refractories according to claim 5, further comprising, as a mixture the solid solution obtained by dissolving Sr components in the CaAl₂O₄.
 8. The binder for monolithic refractories according to claim 7, wherein a total amount of the solid solution obtained by dissolving Ca components in the α-SrAl₂O₄, the solid solution obtained by dissolving Ca components in the β-SrAl₂O₄, and the solid solution obtained by dissolving Sr components in the CaAl₂O₄ is from 10 mass % to 60 mass %, and 40 mass % to 90 mass % of Al₂O₃ is blended thereinto.
 9. The binder for monolithic refractories according to claim 1, wherein at least one selected from a group consisting of SiO₂, TiO₂, Fe₂O₃, MgO, and BaO are included in the binder for monolithic refractories and an amount thereof is 12 mass % or less.
 10. The binder for monolithic refractories according to claim 1, wherein at least one of a dispersant and a hardening retardant is blended into the binder for monolithic refractories.
 11. A monolithic refractory obtained by blending the binder for monolithic refractories according to any one of claims 1 to 10 into a refractory aggregate.
 12. The monolithic refractory according to claim 11, wherein the refractory aggregate includes an ultrafine alumina powder with a particle diameter of from 0.8 nm to 1 μm.
 13. The monolithic refractory according to claim 11, wherein an amount of the binder for monolithic refractories is from 0.3 mass % to 20 mass % with respect to 100 mass % of a total amount of the binder for monolithic refractories and the refractory aggregate.
 14. The monolithic refractory according to claim 13, wherein the amount of the binder for monolithic refractories is from 0.5 mass % to 12 mass % with respect to 100 mass % of the total amount of the binder for monolithic refractories and the refractory aggregate.
 15. The monolithic refractory according to claim 11, wherein further at least one of a dispersant, a hardening retardant, and a hardening accelerator is added.
 16. The monolithic refractory according to claim 15, wherein the dispersant is at least one selected from a group consisting of a polycarbonate-based dispersant, a phosphate-based dispersant, an oxycarboxylic acid, a melamine-based dispersant, a naphthalene-based dispersant, and a lignin sulfonic acid-based dispersant, the hardening accelerator is at least one of an alkali metal salt and aluminate, and the hardening retardant is at least one of boric acid group and silicofluoride.
 17. A construction method of monolithic refractories comprising: blending and mixing the binder for monolithic refractories according to any one of claims 1 to 10 and a refractory aggregate including an ultrafine alumina powder with a particle diameter of 1 μm or less to obtain a monolithic refractory; and constructing the monolithic refractory. 